@phdthesis{Adler2025, author = {Adler, Katharina}, title = {Avian diversity in vineyards - Circannual effects of landscape structure and management practices in viticultural regions}, volume = {2025}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1167}, school = {Hochschule Geisenheim University}, pages = {1 -- 148}, year = {2025}, abstract = {Methods of intensive land use and structural impoverishment of landscapes have been shown to have a strong negative impact on biodiversity in agricultural landscapes. Due to increasing population numbers and growing yield demands on less land, the sustainable management of utilised biotope types in agricultural landscapes has become a key topic of biodiversity research. More than any other bird species group, birds of the agricultural landscape have experienced massive population declines throughout Germany and Europe in recent years. The majority of research projects carried out in this area relate to annual crops. However, permanent crops, such as fruit plantation, vineyards and timber plantations, have received little attention in biodiversity research to date. Due to ongoing climate change, vineyards will also become increasingly important outside the Mediterranean region, replacing more and more semi-natural habitats. This makes it all the more important to understand how these cultures affect biodiversity and how this can be sustainably managed. Wine-growing areas offer potentially attractive living conditions for avifauna: The wooden structures of the vines, greening between the rows of vines and a mosaic with neighbouring unused structures can provide suitable habitat structures for different species. In many cases, however, viticulture is characterised by intensive management regimes with frequent disturbance events such as pesticide application, tillage or mowing of the species-poor green alleys and removal of marginal structures. Various studies show that these factors in crop monocultures have a major influence on bird diversity. The aim of this thesis was to analyse the influence of different landscape structures on the bird community in wine-growing areas and the influence of these bird communities on viticulture in terms of grape damage. The following studies were carried out for this purpose: -A literature study on the main influencing factors already identified in the scientific literature was compiled for both topics. -Two wine-growing regions in Germany (Rheingau and Rheinhessen) were analysed in a case study. Bird species were recorded throughout 2020 and 2021 and then analysed with data on the composition and structure of the landscape, which were collected by digitising orthophotos and verifying them on site. -In a further field study in Napa Valley (CA, USA), grape damage caused by birds in six vineyards was recorded and analysed with data from the landscape as well as vineyard management to determine which structures made grapes particularly enticing as food for birds.}, language = {en} } @phdthesis{Lamberty2025, author = {Lamberty, Anna}, title = {Development of a generic concept for cross chain temperature monitoring using IoT-based sensor technology to optimize the product quality of fresh plant-based produce}, volume = {2025}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1189}, school = {Hochschule Geisenheim University}, pages = {II -- 184}, year = {2025}, abstract = {The objective of this thesis was to develop a generic implementation concept for cross-chain IoT-based temperature monitoring in supply chains of fresh plant-based produce, including a cost-benefit-assessment. In the first step, a literature review was conducted to categorize fresh fruit and vegetables by their product-specific spoilage kinetics in relation to the main influential ambient parameters (temperature, relative humidity, ethylene, CO2, O2, vibration). In addition, the state-of-theart of relevant IoT technology was reviewed. This was followed by a systematic literature review and practical tests in four supply chains, focusing on data transmission reliability, temperature accuracy, location accuracy, battery life and sustainability, to identify technical, process-related and sustainability requirements for IoT-based temperature monitoring systems. Based on those results and a multi-dimensional field analysis including stakeholder interviews, a generic implementation concept was elaborated and validated in a real-world pilot study. Finally, the results of stakeholder interviews were used to create three application scenarios for IoT-based temperature monitoring. The costs and benefits of an IoT implementation were assessed for each scenario. The results highlight the complexity of fresh plant-based produce but also show the potential for optimizing product qualities by using IoT-based temperature monitoring, particularly for berries, leafy vegetables, climacteric fruit and chilling-sensitive products. While suitable IoT technology is available, the variety can make it challenging for supply chain actors to choose the right solution. Here, the identified technical, process-related and sustainability requirements can aid decision-making for potential users and provide development insights for IoT providers. However, needs for improvements of the tested IoT systems were found, particularly regarding data transmission reliability, temperature accuracy and sensor sustainability. The developed generic concept provides a blueprint for practical implementation in supply chains. The validation results confirm its operational feasibility. Further, it was found that IoT-based temperature monitoring can lead to monetary savings by reducing product losses, depending on the specific combination of IoT technology, product, packaging type, data use, and hardware reuse frequency. It must be highlighted that sustainable use of IoT devices enhances potential monetary benefits by avoiding subsequent sensor purchase costs.}, language = {en} } @phdthesis{DELONGHI2024, author = {DE LONGHI, Emilio}, title = {Sensory and chemical characterization of the aroma of Riesling wines}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1121}, school = {Hochschule Geisenheim University}, pages = {i -- XXIX}, year = {2024}, abstract = {Riesling wines are appreciated for their diverse and distinctive aromas, resulting from complex interactions of their numerous volatile components with human olfactory system. However, the volatile composition associated with the aroma properties of Riesling wines has not been fully understood. The aim of this thesis was to advance the characterization of Riesling wine volatile composition, through analytical and sensory approaches. Focusing on the thiol component of Riesling wine, sensory-guided screening by heart-cutting multidimensional gas chromatography mass spectrometry/olfactometry (H/C MDGC-MS/O) of Riesling wine thiol selective extracts, obtained by Ag+ solid-phase extraction (Ag+ SPE), followed by Riesling wine thiol analysis by ultra high-performance liquid chromatography (UHPLC) quadrupole Orbitrap high-resolution mass spectrometry (HRMS) in parallel reaction monitoring (PRM), enabled the identification of twelve volatile odorant thiol candidates in Riesling wine (3-sulfanylhexan-1-ol, 3-sulfanylheptan-1-ol, 3-sulfanylhexyl acetate, 4-methyl- 4-sulfanylpentan-2-one, ethyl 3-sulfanylpropionate, ethyl 2-sulfanylpropionate, trans-2- methyl-3-tetrahydrofuranthiol, 2-methyl-3-furanthiol, benzenemethanethiol, o-toluenethiol, mtoluenethiol, and 2-furfurylthiol). LC-MS analysis empowered to quantify the twelve thiols in a set of Riesling wines (n = 33), highlighting their occurrence at concentrations reaching sensory detection threshold values. Additionally, it allowed the detection of two new monoterpenoid thiols 1-p-menthene-8-thiol and trans-p-menthane-3-one-8-thiol in wine for the first time, two compounds possessing respectively grapefruit and blackcurrant aroma nuances. The odor thresholds of these thiols in model wine were determined at 0.076 ng/L and 22.9 ng/L, respectively. The employed LC-MS analytical method was newly developed for the quantitation of ultra-trace volatile thiols in wine. The proposed procedure, consisting of thiol derivatization by 4,4'-dithiodipyridine (DTDP), followed by thiol-DTDP derivatives isolation by liquid-liquid extraction, allowed rapid sample preparation. Instrument analysis performed using UHPLC quadrupole Orbitrap HRMS offered ultra-selectivity and sensitivity for 19 selected thiols. The analytical performances of the novel method were observed in most cases greater than those of previously developed methods. A comprehensive investigation of the links between volatile composition and sensory properties of Riesling wine was then conducted, combining sensory descriptive analysis with quantitative chemical data from a selection of Riesling wines from Germany and France (n = 27). The results from the quantitative chemical analysis of 77 volatile compounds and 14 basic wine parameters were merged with the sensory scores obtained from the descriptive analysis of the collected wine samples by a German-based experienced panel (n = 18) through partial least squares (PLS) regression. The analyzed volatiles spanned from different molecular families known for their relevance for Riesling wine aroma and included monoterpenes, C13-norisoprenoids, higher alcohols, acetate esters, fatty acid ethyl esters, lactones, light volatile sulfur compounds, and polyfunctional thiols. Selected compounds with higher regression coefficients in relation to Riesling aromatic typicality scoring were supplemented in Riesling wine, up to concentration levels reached by the most typical ranked wines, and were found to be associated with a significant increase of Riesling olfactory typicality perceived by experienced sensory judges (n = 15). Overall, this work has advanced the knowledge about molecular drivers of aroma perception of Riesling wines, pointing out the role of novel potent polyfunctional thiols, in association to other major aroma components of Riesling wines. These findings offer promising prospects for the winemaking industry and for future advancements in Riesling wine aroma research.}, language = {en} } @phdthesis{Hauck2024, author = {Hauck, Katharina}, title = {Challenges of the organic wine sector - A value chain analysis of organic wine in Germany}, volume = {2024}, number = {99}, edition = {1. Auflage}, publisher = {Geisenheimer Berichte}, address = {Geisenheim}, isbn = {ISBN 978 3 934742 91 8}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-898}, school = {Hochschule Geisenheim University}, pages = {II -- 95}, year = {2024}, abstract = {The demand for organic products is continuously increasing, with Germany's organic market reaching 15.9 billion euros, making it the second largest in the world. Concurrently, the organically farmed area in Germany is also expanding. The German wine industry is similarly affected, with the share of organic viticulture more than doubling over the past decade. However, there is a notable disparity in the demand for organic wine compared to other organic foods. This dissertation aims to explain the discrepancy between the increasing area of organically cultivated vineyards and the lack of conscious purchasing of organic wine. The research project investigates the entire value chain of organic wine using qualitative and quantitative methods. It surveys producers about their attitudes and motivations behind converting vineyards to organic farming, and includes feedback from traders to define consumer preferences and future market developments. The study also examines the end consumer's perspective to understand why organic wine is not consciously perceived and purchased. The findings reveal that personal conviction drives winegrowers to switch to or maintain organic farming, but low demand is offset by challenging production conditions and higher costs. Traders are interested in organic wine only if there is demand, and their limited knowledge hinders consumer education.}, language = {de} } @phdthesis{Fackert2024, author = {Fackert, Marcel Monti}, title = {Analyse und Gestaltung der Logistikprozesse in der deutschen Qualit{\"a}tsschaumweinindustrie unter besonderer Ber{\"u}cksichtigung von Digitalisierung und Automatisierung}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1131}, school = {Hochschule Geisenheim University}, pages = {I -- 230}, year = {2024}, abstract = {Diese Dissertation untersucht die logistischen Zusammenh{\"a}nge in den Wertsch{\"o}pfungsstufen der Qualit{\"a}tsschaumweinindustrie in Deutschland. Der Absatz und die Herstellung von Qualit{\"a}tsschaumwein ist im Betrachtungs-zeitraum von 2002 bis heute stetig gestiegen und hat sich im Volumensegment bereits auf wenige große Hersteller konsolidiert. Die Marktstruktur und -teil-nehmer werden aufgezeigt und ihre Motivation hinsichtlich Umsatz, Menge und Herstellqualit{\"a}t genau beschrieben. Die neu entwickelte Sekt Supply Chain visualisiert die verschiedenen logistischen Wertsch{\"o}pfungsketten von der Traube bis zum fertigen Sekt {\"u}ber die Schritte des eigenen Anbaus bzw. dem Zukauf von Rohstoffen, den verschiedenen Herstellungsverfahren und Lagerhaltungsm{\"o}glichkeiten bis hin zur Distribution. Durch explorative Experteninterviews werden logistische Trends in der Digitalisierung, Automatisierung und Nachhaltigkeit f{\"u}r die Branche bewertet. Digitalisierung findet zwar in fast allen Unternehmen statt, jedoch mit unterschiedlichen Ans{\"a}tzen. F{\"u}r alle gemein ist die effizientere Herstellung auf Basis von Echtzeitdaten und Reduzierung der Durchlaufzeiten und Losgr{\"o}ßen f{\"u}r schnellere Reaktionszeiten mit weniger Best{\"a}nden. Die Sekthersteller kommen digital n{\"a}her an den Kunden und produzieren bedarfsgenauer. Bei Sektmanufakturen ist durchg{\"a}ngig ein gesteigertes Qualit{\"a}tsniveau festzustellen, wobei traditionelle Methoden nicht im Widerspruch zur Automatisierung von Prozessschritten zur Steigerung der Flexibilit{\"a}t und Reduzierung von Kapazit{\"a}tskosten wie Personaleinsatz stehen. In der Sekt Supply Chain gibt es in den einzelnen Logistikprozessen viel Optimierungspotential. Dies wird mit zwei Detailbeispielen, der Reduzierung von Verschwendung bei der schlanken Traubenanlieferung des Badischen Winzerkellers und bei der bedarfs- bzw. bestandsoptimierten Prognose bei Rotk{\"a}ppchen-Mumm mit Hilfe des Advanced Planning mit einer daf{\"u}r entwickelten mathematischen Formel aufgezeigt. Trotz aller unternehmensspezifischer Unterschiede und der Heterogenit{\"a}t des deutschen Sektmarktes gibt es doch Gemeinsamkeiten in den logistischen Prozessen unter dem Einfluss der Digitalisierung und Automatisierung.}, language = {de} } @phdthesis{Dahlmann2024, author = {Dahlmann, Melanie}, title = {Entwicklung eines innovativen Fallendesigns f{\"u}r ein Attract-and-Kill Verfahren zur nachhaltigen Bek{\"a}mpfung der Kirschessigfliege Drosophila suzukii im Obst- und Weinbau}, volume = {2025}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1077}, school = {Hochschule Geisenheim University}, pages = {436}, year = {2024}, abstract = {Seit 2008 verursacht die Kirschessigfliege Drosophila suzukii (MATSUMURA 1931) (Diptera: Drosophilidae) aufgrund ihrer polyphagen Lebensweise nicht nur in Europa hohe wirtschaft-liche Verluste vor allem im Stein- und Beerenobstanbau, aber auch im Weinbau. Die invasive Art hat sich weltweit rasant ausgebreitet, vor allem {\"u}ber den Export von Fr{\"u}chten. Eine hohe Vermehrungsrate und die Anpassung an klimatische Bedingungen machen diesen Sch{\"a}dling zu einem ernsthaften Problem f{\"u}r den Pflanzenschutz in Obst- und Weinbaugebieten. Im Gegensatz zu monophag lebenden Schaderregern, stellt die polyphage Lebensweise der Kirschessigfliege eine weitere Herausforderung f{\"u}r eine gezielte und nachhaltige Bek{\"a}mpfung dar. F{\"u}r eine fr{\"u}hzeitige Prognose von Schadschwellen und eine effiziente Bek{\"a}mpfung von D. suzukii, z. B. durch den Einsatz von Insektiziden, ist daher die Kenntnis {\"u}ber biologische Verhaltensparameter sowie {\"U}berwinterungs- und R{\"u}ckzugsgebiete, aus denen der Schadorga-nismus in die Obst- und Weinberge migriert, von großer Bedeutung. In Deutschland wurden bereits mehr als 50 Wirtspflanzen aus Kultur- und Wildpflanzen als Vermehrungshabitat identifiziert. Aufgrund des anhaltenden Mangels an alternativen Methoden zur Bek{\"a}mpfung von D. suzukii, ist auch das Wissen um die Wirksamkeit von Insektiziden entscheidend f{\"u}r ein optimal angepasstes Bek{\"a}mpfungsmanagement. Ziel der vorliegenden Dissertation war es, visuelle und olfaktorische Lockmittel f{\"u}r eine nachhaltige und umweltfreundliche Bek{\"a}mpfungsstrategie gegen Drosophila suzukii zu ent-wickeln, die auf der Methode des Attract-and-Kill (engl. Anlocken-und-Abt{\"o}ten) Verfahrens basiert. Der Schwerpunkt lag auf der Entwicklung eines geeigneten Fallendesigns und eines attraktiven K{\"o}ders, welcher in Kombination mit einem (biologischen) insektiziden Wirkstoff als Fraßk{\"o}der in Fangfallen oder zur Blattapplikation verwendet werden k{\"o}nnte. Die Kombi-nation aus Lockstoff und Insektizid soll dazu beitragen, den Einsatz von Pflanzenschutz-mitteln zu reduzieren und die Vermehrungsrate von D. suzukii nachhaltig zu senken. Im Rahmen der vorliegenden Dissertation ist es gelungen, ein Fallendesign zu entwickeln, das insbesondere f{\"u}r Drosophila suzukii Weibchen attraktiv ist. Das Design, welches auf kugel-f{\"o}rmigen Objekten in unterschiedlichen Farben auf rotem Hintergrund basiert, zeigte eine geschlechterspezifische Attraktivit{\"a}t durch eine signifikant h{\"o}here Anzahl weiblicher Indi-viduen im Vergleich zu D. suzukii M{\"a}nnchen innerhalb der Falle. Diese positive Eigenschaft des neuen Fallendesigns wurde in Gew{\"a}chshaus- und Halbfreilandversuchen festgestellt und war ebenfalls unter Freilandbedingungen reproduzierbar. Die Entwicklung eines Fraßk{\"o}ders (Phagostimulans) aus weitestgehend nat{\"u}rlichen Inhaltsstoffen zeigte unter Laborbedingun-gen vielversprechende Ergebnisse f{\"u}r einen m{\"o}glichen Einsatz im Rahmen eines Attract-and-Kill Verfahrens, z. B. als Fraß-, bzw. Eiablagek{\"o}der. Der K{\"o}der zeigte eine hohe Attraktivit{\"a}t im Vergleich zu einer nat{\"u}rlichen Wirtsfrucht (Choice-Test) sowie eine Wirkung auf die Mortalit{\"a}tsrate adulter D. suzukii (M{\"a}nnchen 99 \% und Weibchen 70 \% Mortalit{\"a}t nach 72 h im Vergleich zur unbehandelten Kontrolle). Dar{\"u}ber hinaus konnte ein Einfluss des Fraß-Eiablage-K{\"o}ders auf die larvale Entwicklung und eine Verringerung der Verpuppungsrate nachgewiesen werden. Erg{\"a}nzend zu der Entwicklung m{\"o}glicher Lockstoffe f{\"u}r den Einsatz im Attract-and-Kill Verfahren wurden Laborversuche mit adulten D. suzukii und L1-Larven durchgef{\"u}hrt, um die Wirksamkeit verschiedener Pr{\"u}fsubstanzen auf die Fekundit{\"a}t, Repro-duktionsrate sowie die Mortalit{\"a}t zu untersuchen. Die Versuche mit dem Wirkstoff Azadirachtin A (NeemAzal® technical, NeemAzal®-T/S) zeigten nach oraler Aufnahme einen Effekt auf die Fekundit{\"a}t und auf den Larvenschlupf. Auch die larvale Entwicklung von D. suzukii in einem festen Medium wurde unter dem Einfluss von Azadirachtin A reduziert bzw. verhindert. Ein Einfluss des Wirkstoffes auf die Mortalit{\"a}t adulter Versuchstiere konnte nicht festgestellt werden. Die Verwendung des Pr{\"a}parates SpinTor® (Wirkstoff Spinosad) in Laborversuchen f{\"u}hrte sowohl bei adulten D. suzukii (nach 24 bis 48 h) sowie bei D. suzukii L1-Larven (nach 24 h) bei Kontakt mit einem behandelten Medium zu einer Mortalit{\"a}tsrate von 100 \%. Das Konservierungsmittel Sorbins{\"a}ure, welches als weiteres Pr{\"u}fmittel getestet wurde, zeigte bei Kontakt oder nach oraler Aufnahme keine Wirkung auf die Mortalit{\"a}t adulter D. suzukii. Die orale Aufnahme von Sorbins{\"a}ure f{\"u}hrte jedoch zu einer schwach signifikanten Reduktion der Eiablage und des Larvenschlupfes gegen{\"u}ber der Anzahl Eier und Larven der unbehandelten Kontrolle und zu einer Mortalit{\"a}tsrate von 100 \% bei L1-Larven (nach 24 h), wenn sie einem mit Sorbins{\"a}ure behandelten Medium ausgesetzt waren. Die Ergebnisse aus der vorliegenden Dissertation sollen weitere Forschungsvorhaben unterst{\"u}tzen und dazu beitragen, die Entwicklungen von Fraßk{\"o}dern bzw. K{\"o}der-Insektizid-Mischungen und K{\"o}derstationen f{\"u}r eine effiziente Attract-and-Kill Strategie zur nachhaltigen Bek{\"a}mpfung der Kirschessigfliege Drosophila suzukii zu optimieren.}, language = {de} } @phdthesis{Le2025, author = {Le, Ngoc Duc}, title = {Investigation of the potential allergenicity and coloration of peanut and hazelnut regarding different high-temperature processing methods}, volume = {2025}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1055}, school = {Hochschule Geisenheim University}, pages = {i -- 259}, year = {2025}, abstract = {Peanut and hazelnut are important sources of protein and are often processed using methods like roasting, baking, frying, and cooking. However, since both are major allergens, it is crucial to study how processing affects their potential to cause allergic reactions. This doctoral research is part of the ErdHase project, which aims to understand the impact of high-temperature processing on the biochemical and physical properties these nuts. The first goal of the study was to determine suitable parameters to define the processing degree of peanuts and hazelnuts, such as L* (lightness) and the browning index (BI). Their reference values, which depend on raw materials and market preferences, were derived based on commercial products and experimental roast models. The study employed various processing methods including drum roasting, infrared roasting, deep frying (for peanut), and fluid-bed roasting (for hazelnut). To study the effects of temperature and time on coloration and moisture, response surface methodology (RSM) was used. This approach was considered effective in reducing the number of experiments needed while maintaining reliable results. As temperature and time increased, the moisture content decreased, and the browning increased, which was consistent with prior research. Additionally, the study found that the ∆E2000 total color difference was more accurate than ∆E76 for assessing the total color difference between processed samples and commercial products. Combining all the collected data, it could be seen that for both Virginia and Runner peanuts and hazelnut, infrared roasting reduced the MC faster and drum roasting affected the color more drastically at the same temperature compared to other approaches. Deep frying of peanut and fluid bed roasting of hazelnut requires higher temperature profiles to achieve a comparable effect. The second part of the research focused on optimizing protein extraction from both raw and processed peanuts and hazelnuts. An extraction protocol using Tris-containing buffer with mild heating was developed and optimized using RSM, yielding good results with minimal denaturation of proteins. The study also showed the protein composition of processed peanuts and hazelnuts using SDS-PAGE and NativePAGE. Processing methods like roasting and frying reduced the protein yield, and allergen bands were detected, although patient-specific IgE binding varied. Further research involved the development of buckwheat-based foods (cream alternative and cookies) to test for the allergenicity in ELISA. Infrared and drum roasting was found to have the greatest impact on allergen recovery. Additionally, a food-grade protease was applied for improving allergen extraction. This enzyme significantly increased allergen recovery without affecting ELISA performance, offering a potential solution to the problem of low extractability of processed allergens. In summary, the presented doctoral thesis, on the one hand, provided additional investigations regarding different high-temperature processing methods on coloration and moisture content of peanut and hazelnut. It confirmed previous observation, defined a new approach of combining L* and BI to evaluate processed products. On the other hand, on the biochemical aspect of processed peanuts and hazelnuts, this work provided an optimized extraction protocol that potentially works for a wide spectrum of processed samples. In addition, incurred buckwheat-based products and enzyme-assisted extraction for ELISA showed promising results for future applications regarding their potential allergenicity.}, language = {en} } @phdthesis{Koerner2025, author = {K{\"o}rner, Tobias}, title = {Effects of Thermopriming on Resilience to Subsequent Stress Conditions in Tomato (Solanum lycopersicum L.)}, volume = {2025}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1027}, school = {Hochschule Geisenheim University}, pages = {2 -- 116}, year = {2025}, abstract = {Die zunehmende H{\"a}ufigkeit von Hitzewellen und anderen extremen Wetterereignissen bedroht die Ernten weltweit. Herk{\"o}mmliche Anbaumethoden sind nur begrenzt an diese klimatischen Ver{\"a}nderungen angepasst. Daher sind innovative Ans{\"a}tze gefragt, um die Stressresilienz unserer Nutzpflanzen nachhaltig zu erh{\"o}hen. Ein solcher Ansatz ist das Thermopriming, bei dem Pflanzen kontrolliertem Hitzestress ausgesetzt werden. Dieser f{\"u}hrt zur Anreicherung sch{\"u}tzender Pflanzeninhaltsstoffe und verbessert somit die Resilienz der Pflanzen gegen{\"u}ber zuk{\"u}nftigen Stressbedingungen. Diese Dissertation gibt Einblicke in optimierte Thermopriming-Bedingungen f{\"u}r Tomatenjungpflanzen und die langfristigen Auswirkungen von Thermopriming auf Pflanzenwachstum, -entwicklung und -ertrag und schließt damit eine L{\"u}cke in einem bisher wenig untersuchten Forschungsgebiet. Das erste Kapitel konzentriert sich auf die Optimierung des Thermopriming-Regimes, um die Stressresilienz bei Tomatenjungpflanzen zu erh{\"o}hen und gleichzeitig Wachstumshemmungen zu minimieren. Die Experimente zeigten, dass 90-min{\"u}tiges Thermopriming den besten Kompromiss zwischen der Erh{\"o}hung der Flavonolanreicherung in den Bl{\"a}ttern und der Verringerung von Wachstumsverlusten bietet. Diese Ergebnisse zeigen, dass Thermopriming eine praktikable Methode zur Integration in die gartenbauliche Pflanzenproduktion ist, um die langfristige Stressresilienz dieser Modellpflanze zu erh{\"o}hen und die negativen Auswirkungen des Klimawandels zu mildern. Das zweite Kapitel konzentriert sich darauf, wie Thermopriming die Stressresilienz von Tomatenpflanzen erh{\"o}ht und wie die Thermopriming-Behandlung mit anschließendem Salzstress interagiert. Die Ergebnisse zeigten eine signifikante Anreicherung von sch{\"u}tzenden Phenolen und Flavonolen in den Bl{\"a}ttern von thermogeprimten Pflanzen, insbesondere als Reaktion auf den nachfolgenden Salzstress. Diese Ergebnisse zeigen, dass Thermopriming das Potenzial hat, die Produktivit{\"a}t und Qualit{\"a}t von Ernten unter Umweltstress zu sichern und somit von entscheidender Bedeutung f{\"u}r einen nachhaltigen Gartenbau werden kann. Das dritte Kapitel vergleicht die Wirksamkeit von Thermopriming zur Erh{\"o}hung der pflanzlichen Toleranz mit der des chemischen Elicitors Benzothiadiazol (BTH) bei anschließendem Salzstress. Die Studie zeigte, dass BTH zwar die Stresstoleranz bis zu einem gewissen Grad erh{\"o}hte, jedoch das Wachstum und die Fruchtentwicklung negativ beeinflusste. Diese Ergebnisse weisen darauf hin, dass die Dauer der Erholungsphase und der Zeitpunkt des Folgestresses eine entscheidende Rolle f{\"u}r die Wirksamkeit und den Einsatz von Thermopriming spielen. Die Integration von Thermopriming in die Pflanzenproduktion steht im Einklang mit mehreren Nachhaltigkeitszielen der Vereinten Nationen, insbesondere mit Ziel 2 (Kein Hunger), das darauf abzielt, den Hunger zu beenden, die Ern{\"a}hrungssicherheit zu erreichen, die Ern{\"a}hrung zu verbessern und eine nachhaltige Landwirtschaft zu f{\"o}rdern. Es unterst{\"u}tzt auch Ziel 13 (Maßnahmen zum Klimaschutz), das dringende Maßnahmen zur Bek{\"a}mpfung des Klimawandels und seiner negativen Auswirkungen fordert. Dar{\"u}ber hinaus unterst{\"u}tzt Thermopriming die Ziele des European Green Deals, bis 2050 klimaneutral zu werden, die EU-Biodiversit{\"a}tsstrategie f{\"u}r 2030, indem es biodiversit{\"a}tsfreundliche Praktiken f{\"o}rdert, und die EU-Strategie „Vom Hof auf den Tisch", indem es Treibhausgasemissionen reduziert und die Nachhaltigkeit der Pflanzenproduktion und die Vitalit{\"a}t der {\"O}kosysteme f{\"o}rdert. Auf diese Weise kann ein gerechtes, gesundes und umweltfreundliches Lebensmittelsystem unterst{\"u}tzt werden. Zudem kann Thermopriming durch die Verringerung der Abh{\"a}ngigkeit von Pflanzenschutzmitteln und die F{\"o}rderung des {\"o}kologischen Landbaus die negativen Auswirkungen auf die Umwelt und den {\"o}kologischen Fußabdruck verringern. Thermopriming ist eine vielversprechende Strategie, um die Resilienz von Pflanzen gegen{\"u}ber dem Klimawandel zu erh{\"o}hen. Daher sollte die Integration von Thermopriming in die Pflanzenproduktion von politischen Entscheidungstr{\"a}gern und Praktikern in Betracht gezogen werden, um eine nachhaltige Landwirtschaft zu unterst{\"u}tzen, die Abh{\"a}ngigkeit von chemischen Pflanzenschutzmitteln zu reduzieren und die Ernteertr{\"a}ge und -qualit{\"a}t unter verschiedenen (extremen) Umweltbedingungen zu verbessern.}, language = {en} } @phdthesis{Stollberg2024, author = {Stollberg, Maren}, title = {Vertical planting design: The suitability and microclimatic effect of perennials in a textile living wall system.}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-924}, school = {Hochschule Geisenheim University}, pages = {I -- 211}, year = {2024}, abstract = {Urban green infrastructure has gained significant attention in the context of adaptation to climate change because of its positive effects. One approach to enhancing urban green infrastructure is through the use of Living walls (LW), also known as vertical greenery systems. While considerable knowledge and studies on traditional green facades already exist, there is limited information available on LW. Both green facades and LW are associated with numerous well-documented benefits (e.g., biodiversity and clean air), but these benefits depend on the functionality and vitality of the plants. Our knowledge of plants suitable for LW is limited to only a few climate zones and empirical values that lack confirmed validity. To address this gap, we conducted a three-year experiment using a novel, modular LW system on experimental walls exposed with different exposures. The aim of the research was to develop a textile-based, substrate-free Living Wall, which displays a perennial, attractive and diverse plant image and contributes to cooling. In this experiment, we documented the development of the plants, assessed their suitability, and measured the effect of the plants on the ambient temperature. The experiment took place over three years (2017-2019) in Geisenheim, Germany, which has a temperate oceanic climate and falls under the winter hardiness Zone 8a. For the LW system, we utilized a textile-based mat without soil (1 m²) and selected plants from wet/fresh habitats to enhance evaporative cooling. We maintained frequent irrigation with a nutrient solution, resulting in the mat being consistently overwatered. Based on common designs used in landscape architecture and on the conditions of wet habitats, we created three variants: one which was seeded: "Meadow" and two plant modules: "Cascade" and "Ground Cover". Together these modules consisted of 34 perennials and geophytes. Additionally, we sowed seed mixtures of over 30 species on the textile mat (Meadow/Seeding). We also included a Control group without plants, in which moss and weeds developed and were partially removed. After a pre-growing period on horizontal greenhouse tables, we placed the green mats vertically on experimental walls facing north, south, east, and west. Four replicates of each variant were randomly installed. We assessed plant development using various methods, including visual evaluation of aesthetics and growth form, height measurements, photographs, analysis of species coverage and visibility, canopy analysis, winter survival rate, biomass measurement, root position, and leaf area. Additionally, we employed temperature sensors and an infrared (IR) camera to measure the temperature effects of the plants on and of the ambient temperature under different setups. Through the experiment, we gained valuable insights into the techniques, cultivation, and maintenance of LW. Overall, we observed differences in plant development depending on the exposure, season, plant variant, and spontaneous vegetation. The tested plants exhibited a special vertical growth form and height. We noticed delayed growth on the north exposure, with complete coverage achieved in the third year. The south exposure showed particularly high growth, while the east and west exhibited similar but slightly lower growth compared to the south. The perennials retained their visual appearance throughout the year, with almost all variants looking attractive from May to September. Until the onset of winter, all variants had an appealing appearance. Unexpectedly, we observed the establishment of moss. Most plants survived the mild winters (2018/2019), although a cold winter (2017/1018) with a late frost resulted in damage and mortality for many plants. We conducted a detailed analysis of the different plant variants, as follows: The Ground cover variant exhibited an attractive appearance and foliage decoration throughout the year. At the east, west, and north exposures, the plants showed an attractive appearance shortly after winter, while on the south wall, it took until May for the species to start regrowing. In particular, Waldsteinia ternata displayed a nice leaf texture and, together with Pachysandra terminalis, was the most visually appealing. Ajuga tenorii 'Mauro', Alchemilla caucasica, Glechoma hederacea, and Geum coccineum 'Carlskaer' demonstrated beautiful ornamental effects and flowered during the summer. The Cascade variant showcased its attractiveness during the summer season, as most of the plants became less prominent during the winter. We observed that Tellima grandiflora 'Rubra' and Heuchera Hybrid 'Purple Petticoats' were the most visually appealing in this variant. Hosta sieboldii 'Harry van Trier' exhibited a pleasing ornamental effect and flowered during the summer. The ferns exhibited delayed growth but gradually developed a nice leaf texture. Self-settled moss complemented the planting, covering the entire mat. In the Meadow / Seeding variant, we observed increasing growth in height and vegetation coverage that extended from April to October. Initially, we sowed 32 different plant species, but only 10 were able to establish and become visible. These included Galium (album and palustre), Lycopus europaeus s. str., Stachys palustris, Anthoxanthum odoratum s. str., Festuca spp., and Poa spp. It is important to follow maintenance steps for the Meadow-LW. We noticed that the vegetation recovered within a few weeks after cutting. We recommend one complete cut during the summer and the removal of dead plant material after the frost period ends in spring. To examine the temperature effects of the plants on the ambient temperature and the climatic conditions to which they were exposed, we measured the temperature in different setups. The vegetation temperature depends on factors such as air temperature, measurement position, planting variant, and plant species. We observed a cooling effect only at a short distance from the LW, indicating a microclimatic impact. In conclusion, it is possible to effectively green a textile-based, soilless LW system. However, an automated irrigation system and regular monitoring and maintenance are essential. We identified suitable perennial species for each exposure and compiled a list of plants suitable for LW, along with their specific requirements. Seeded meadow-LW can easily be established. Furthermore, we recommend continuing our methodological approaches to obtain temperature measurements in LW in future studies.}, language = {mul} } @phdthesis{Payan2023, author = {Payan, Claire}, title = {Acidification of musts and wines by fumaric acid: Impact of its addition on the chemical and sensory characteristics of varietal wines in the frame of climate change}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-876}, school = {Hochschule Geisenheim University}, pages = {I -- 243}, year = {2023}, abstract = {Climate change is affecting the composition of grape berries and has led to imbalances in the wine matrix, with an increase in alcohol content and a significant decrease in the acidity of wines. In this context, finding solutions to acidify musts and wines is crucial to maintain their stability, preservation, and sensory quality. The main goal of this study was to test the addition of an alternative acid: fumaric acid for must and wine acidification, and to assess its impact on the chemical and sensory characteristics of wines from different grape varieties and origins. A secondary objective was to study the use of fumaric acid to enhance wine preservation, either as a reduction or as an alternative to the addition of sulfur dioxide (SO2) in traditional winemaking and wine preservation. A preliminary study on the chemical properties to define the solubility and acidifying power of fumaric acid, in comparison to tartaric, malic, and lactic acids, was carried out in various hydro-alcoholic matrices, musts, and wines (both white and red). Additionally, a study on its sensory properties was conducted. A simple, quick, reliable, and validated routine analysis method using high-performance liquid chromatography with UV detection (HPLC-UV) was also developed to quantify fumaric acid in various types of wines. This method has a detection limit of 0.2 mg/L and a quantification limit of 0.3 mg/L, with both inter and intra-day repeatability showing an RSD ≤ 2\%. This research work also allowed the evaluation of the impact of adding fumaric acid to Cabernet Sauvignon red wine, compared to the addition of tartaric acid, at different stages of winemaking: during vatting and just after racking. The results of this first study helped understand the role of fumaric acid in winemaking steps, particularly its metabolism when added before alcoholic fermentation. A second study concerns the addition of fumaric acid at different doses (1 g/L and 2 g/L), compared to tartaric acid (1.25 g/L and 2.5 g/L), before bottling Cabernet Sauvignon red wine, revealing its effectiveness in pH control and its potential to reduce the use of SO2. The results of this second experiment revealed a significant impact of adding fumaric acid on phenolic compounds, particularly catechin and epicatechin, which are maintained at higher concentrations over time compared to the control and the modalities with tartaric acid. Finally, the use of fumaric acid in white winemaking, specifically on M{\"u}ller-Thurgau (a German grape variety, Riesling x Sylvaner), was studied. The addition of fumaric acid effectively inhibited malolactic fermentation as effectively as the addition of SO2. The results indicate that adding fumaric acid during preservation and bottling appears as promising alternatives for wine acidification and more sustainable oenological practices that reduce the use of SO2. The concrete results obtained justify the inclusion of must and wine acidification with fumaric acid by the OIV in the International Code of Oenological Practices of the OIV. Further studies should refine the use and functionalities of fumaric acid on musts (in particular) and wines.}, language = {en} } @phdthesis{Ponchon2024, author = {Ponchon, Mathilde}, title = {The entomopathogenic fungus Metarhizium robertsii and its endophytic potential in grapevine to regulate radicicole grape phylloxera populations}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim University}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-865}, school = {Hochschule Geisenheim University}, pages = {3 -- 212}, year = {2024}, abstract = {Grape phylloxera Daktulosphaira vitifoliae destroyed 30\% of the European vineyard by the end of the 19th century, attacking the woody roots of the grapevine Vitis vinifera (L.). To date, grafting grapevine on American resistant rootstocks is the leading solution to control the pest. However, grape phylloxera is present in most wine-growing soils and remains a threat in regions planted with non-grafted vines. Thus, alternative control solutions are investigated. The entomopathogenic fungus Metarhizium robertsii is known for its capacity to parasitize insects. Besides, the fungus can colonize plant rhizosphere and establish as an endophyte (i.e., within plant tissues) in many plant species. The thesis aimed to investigate if M. robertsii could persistently associate with the rhizosphere and as an endophyte in non-grafted grapevine V. vinifera without harming its growth while preventing the development of the grape phylloxera radicicole forms. Four M. robertsii strains native to four different vineyards were used and came from: i) the center-West Argentina (MsoilAR4.3), ii) the south of Australia (M224B), iii) the south-west of France (EF3.5(2)) and iv) the west of Germany (EF047). Greenhouse experiments were conducted to assess the association between M. robertsii and potted non-grafted grapevines. First, the comparison of the kinetic of grapevine rhizosphere and endosphere colonization was made, comparing the strain EF3.5(2) with a laboratory strain non-native to the vineyard (ARSEF-2575-GFP) to evaluate if a vineyard-native strain had a more durable colonization. Droplet Digital PCR (ddPCR), a culture-based method, and confocal imaging of root segments were used to characterize the associations. The strain EF3.5(2) had a higher establishment in the rhizosphere and root-endosphere of non-grafted grapevine than the strain ARSEF-2575-GFP. Both strains were established for up to 96-98 days post-inoculation (dpi) in both compartments. Then, the potential of association with the non-grafted grapevine of all four-vineyard native M. robertsii strains was compared. The rates of rhizospheric colonization at 68-70 dpi ranged from 60\% for the Argentinian MsoilAR4.3 strain, 65\% for the Australian M224B strain, 76\% for the French EF3.5(2) strain, to 100\% for the German EF047 strain. The rates of root endosphere colonization were 14\%, 10\%, 5\%, and 33\% at 68-70 dpi, respectively. No significant differences of rhizosphere and root-endosphere colonization between tested strains were recorded. Also, the fungal association unaffected the grapevine's growth and leaf pigment content during the experimental period. Finally, the effect of direct parasitism of the strain EF3.5(2) on the survival and development of radicicole grape phylloxera clone 'Pcr7' was evaluated in the woody root section bioassay. Depending on the method used to infect the insect, a significant reduction of 90 \%, 70 \%, and 86\% in survival probability was found, and 92\%, 89\%, and 93 \% in reduction of adults' development compared with control treatments. Also, the symptoms induced by grape phylloxera on non-grafted grapevines co-inoculated with M. robertsii were reduced by 91\% (mean of 4.8 ± 8.4 nodosities) compared with the phylloxera infested-plants (mean of 52.7 ± 50.7 nodosities). The qPCR analysis performed on grapevine inoculated with strain EF3.5(2) showed after 24h, the up- regulation of the VvWRKY-75, VvPR3.2, VvPR4, and VvG1, which are phylloxera-responsive defense genes involved in the resistance against phylloxera. In conclusion, M. robertsii's persistent association with non-grafted grapevine represents an alternative protection strategy against radicicole grape phylloxera, especially for wine-growing regions planted with non-grafted vines. Further field experiments should be carried out to determine the environmental factors affecting the effectiveness and persistence of M. robertsii associated with grapevine.}, language = {en} } @phdthesis{Moulis2024, author = {Moulis, Pierre}, title = {Exploration of the phenomena associated with the production of pyrrole and pyridine derivatives responsible for mousy off-flavours in wine}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-880}, school = {Hochschule Geisenheim University}, pages = {I -- 152}, year = {2024}, abstract = {In den letzten Jahren ist die Nachfrage der Verbraucher nach Bio-Lebensmitteln weiter gestiegen. Die Akteure des Weinsektors achten auf diese Erwartungen. In der Weinproduktion ist ein R{\"u}ckgang in der Anwendung bestimmter Maßnahmen, die sich direkt auf die Weinqualit{\"a}t auswirken k{\"o}nnen, zu verzeichnen. So hat beispielsweise der „M{\"a}uselton" bei Weinen mit reduziertem Sulfitgehalt zugenommen. Derzeit scheinen drei Molek{\"u}le Verursacher dieses Defekts zu sein: 2-Acetylpyrrolin (APY), 2-Acetyltetrahydropyridin (ATHP) und 2-Ethyltetrahydropyridin (ETHP). Die durchgef{\"u}hrte Forschungsarbeit, die chemische, mikrobiologische und {\"o}nologische Ans{\"a}tze kombiniert, liefert Antworten auf die Mechanismen des Auftretens dieses Fehltons im Wein. Um Antworten zu finden, wurden Methoden zur Quantifizierung der N-Heterozyklen, die f{\"u}r den „M{\"a}uselton" verantwortlich sind, mithilfe von SBSE-GC-MS-Techniken entwickelt. Die Bestimmungsmethode f{\"u}r Wein erm{\"o}glichte es, diese Substanzen in 74 verschiedenen Weinen zu quantifizieren. Die zweite Analysenmethode ist auf ein chemisch definiertes Medium abgestimmt, das alle bisher bekannten Vorstufen des „M{\"a}useltons" enth{\"a}lt. Sie erm{\"o}glicht es, Mikroorganismen unter standardisierten Bedingungen auf ihre F{\"a}higkeit zu testen, einen „M{\"a}uselton" zu erzeugen. Mit diesen Methoden konnte gezeigt werden, dass das Verh{\"a}ltnis der beiden Tautomere von 2-Acetyltetrahydropyridin nicht von den Unterschieden zwischen dem pH-Wert des Weines und der Mundh{\"o}hle beeinflusst wird. Mikroorganismen wurden aus 25 Weinen mit „M{\"a}uselton" isoliert. Die am h{\"a}ufigsten anzutreffenden Arten sind Saccharomyces cerevisiae, Oenococcus oeni oder Brettanomyces bruxellensis. Von den 353 isolierten Mikroorganismen sind nur St{\"a}mme der Arten B. bruxellensis, Lentilactobacillus hilgardii und Oenococcus oeni in der Lage, Substanzen, die einen „M{\"a}uselton" verursachen, im Modellmedium zu produzieren. Anschließend wurden St{\"a}mme aus der Sammlung, die zu diesen drei Arten geh{\"o}rten, unter denselben Bedingungen untersucht. Die Ergebnisse zeigen, dass die Konzentrationen und Verh{\"a}ltnisse der drei N-Heterozyklen signifikante Unterschiede zwischen den Arten aufweisen, dass jedoch alle untersuchten St{\"a}mme (22 St{\"a}mme von B. bruxellensis, 10 St{\"a}mme von L. hilgardii, 20 St{\"a}mme von O. oeni) die F{\"a}higkeit haben, mindestens eine der drei Komponenten zu produzieren. Weitere Versuche in Modellmedien haben gezeigt, dass es bei der Produktion m{\"a}uselnder Substanzen zu einer Interaktion zwischen Mikroorganismen kommen kann. Die Untersuchung dieser Wechselwirkungen wurde im Weinmilieu fortgesetzt. Ein Ugni blanc Most wurde mit zwei verschiedenen Saccharomyces cerevisiae St{\"a}mmen vinifiziert. Anschließend wurde die Produktion der m{\"a}uselnden Komponenten {\"u}ber 24 Tage verfolgt. Die Ergebnisse zeigten, dass unabh{\"a}ngig von den produzierenden Mikroorganismen einer der beiden S. cerevisiae St{\"a}mme zur Entwicklung von Bedingungen beitr{\"a}gt, die eine h{\"o}here APY-Produktion im Wein erm{\"o}glichen. Schließlich wurden Produktionskinetiken im Modellmedium durchgef{\"u}hrt, um festzustellen, in welchem physiologischen Stadium B. bruxellensis diese Verbindungen produzieren kann. Die Produktion von ATHP verl{\"a}uft nicht linear. Die Verbindung tritt punktuell in hohen Konzentrationen auf, insbesondere zu Beginn der station{\"a}ren Wachstumsphase, und verschwindet dann wieder. Es wurden Hypothesen {\"u}ber die physiologische Rolle dieser Verbindung aufgestellt. Schl{\"u}sselw{\"o}rter: M{\"a}uselton; Weine; Brettanomyces bruxellensis; Milchs{\"a}urebakterien; Organoleptische Abweichungen}, language = {en} } @phdthesis{Dries2024, author = {Dries, Leonie}, title = {Microbial structure and diversity in the rhizosphere of grape vines (Vitis vinifera L.)}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-827}, school = {Hochschule Geisenheim University}, pages = {II -- 133}, year = {2024}, abstract = {Microorganisms are a substantial component of the rhizosphere, and the activity and composition of rhizosphere microbial populations markedly affect interactions between plants and the soil. In addition, the microbiota of the rhizosphere can positively influence plant development, growth and vitality. In vineyards, management practices influence both grapevine root growth directly and the rhizosphere microbiota, but the exact mode of action is largely unknown. Recently, however, two new research approaches are increasingly coming into focus to enhance the grapevine growth and health: plant engineering and rhizosphere engineering (Chapter 1). In plant engineering, knowledge about plant-microbiome interactions is used for plant breeding strategies. In rhizosphere engineering, microbial communities are modified by adding specific fertilizers, nutrients, or by bio-inoculation with certain bacteria and/or fungi. Taken together, these new methods suggest a potential for reaching a more sustainable development of a pesticide- and fertilizer-reduced viticulture in the future. Consequently, the aim of this study was to investigate the bacterial rhizobiome of grapevines (Vitis vinifera L.) under different experimental designs. By characterizing the bacterial 16S rRNA gene, a statement on the existing bacterial communities and their diversity can be made and compared under different environmental conditions. For this, a method has to be established that allows to obtain rhizosphere and root material of grapevine plants, and to prepare it for sequencing and further analyses. This applies both to grapevines cultivated in greenhouses under controlled conditions as well as to variants under field conditions. The experimental designs aimed to gain knowledge regarding the bacterial diversity of the grapevine rhizosphere including different grape varieties, different grapevine rootstocks as well as different fertilization measures. The first experiment aimed to investigate the variability of the rhizosphere microbiome resulting from the genotype of the rootstock while minimizing the effect of all other environmental factors. This was made possible by investigating four ungrafted grapevine rootstock varieties of the same age, grown on the same soil under the same climatic conditions and managed identically. The bacterial communities associated with the rhizosphere of the rootstocks 1103 Paulsen, 140 Ruggeri, 161-49 Couderc, and Kober 5BB were characterized with the amplicon based sequencing technique, targeting regions V4-V5 of 16S rDNA gene. The four rootstocks showed similarities concerning the structure of the bacteria assemblage (richness and evenness). Nonetheless, differences were detected in the composition of the bacterial communities. Indeed, all investigated rootstocks recruited communities with distinguishable traits, thus confirming the role of rootstock genotype as driver of the bacteria composition (Chapter 2). In order to disentangle the effect of scion and rootstock, the rRNA (V4-V5 region of 16S rRNA) extracted from the rhizosphere of the grape varieties Riesling and Mueller-Thurgau ungrafted vs. grafted on different rootstocks were sequenced in three experimental set-ups in two different years. The bioinformatic analysis with tools designed to be robust for compositional data showed, that the investigated rootstocks or scions or combinations, respectively, recruited bacterial communities with distinguishable traits. Statistical differences were revealed between ungrafted Riesling and Mueller-Thurgau, and between grafted Riesling and ungrafted Riesling, and ungrafted Mueller-Thurgau and grafted Mueller-Thurgau. Thus, confirming the role of scion and rootstock genotype as a driver of the structure and composition of bacterial communities in the rhizosphere of grapevines (Chapter 3). In order to investigate the impact of different levels of nitrogen (N) fertilization on the rhizosphere microbiome an experimental vineyard with vines (Vitis vinifera L. cv. Pinot Noir) in large containers was examined in 2020 and 2021 at bud break. The vines were fertilized with two different levels of nitrogen added per year (N0 25 kg/ha and N1 75 kg/ha) individually. In order to examine the respective bacterial communities, rhizosphere material was sampled and a subsequent RNA-extraction followed by next generation sequencing was performed. The study revealed significant differences in the bacterial communities in the rhizosphere regarding fertilization levels and sampling depths. The results may help to understand the effect of nitrogen fertilization on the microbiome and, in the long term, reduce fertilization in viticulture, leading to more sustainable vine management (Chapter 4). Hence, superordinate, the future aim is to use new insights to enable more precise plant nutrition in the form of more accurate fertilization recommendations in order to reduce the associated costs in an economical and environmentally friendly way. A more precise knowledge of the specificity and dynamics of the grapevine rhizosphere microbiome under different management practices, grape varieties, rootstocks, and fertilization levels, should enable targeted adaptation strategies for increasingly frequent extreme years leading to a more sustainable viticulture.}, language = {en} } @phdthesis{Badura2024, author = {Badura, Jennifer}, title = {Characterization, regulation and genetic modification of the synthesis of aroma compounds in non-conventional wine yeasts}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim University}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-809}, school = {Hochschule Geisenheim University}, pages = {II -- 223}, year = {2024}, abstract = {Yeasts belonging to the genus of Hanseniaspora are widespread in nature and are generally part of the microbiome of ripe fruits, such as apples, pears and grapes. Hanseniaspora spp. form 50-75\% of the microorganisms found at the onset of grape must fermentations, H. uvarum often being the most abundant. H. uvarum is also a common isolate from other fruits, such as oranges, pineapples, mangoes, apples and pears. Since H. uvarum, known for producing high amounts of acetic acid and ethyl acetate, dominates the onset of spontaneous grape must fermentations, it greatly influences the aroma profile of wines. Besides its important role in fermentations, more biotechnological research has been reported in recent years, highlighting the universal value of H. uvarum beyond the beverage industry. In this thesis, I characterized the aroma-production profile of seven different Hanseniaspora spp. in simultaneous co-fermentations with Saccharomyces cerevisiae. Significant differences could be detected between fermentations using Hanseniaspora spp. belonging to the fast-evolving lineage (FEL) and the slow-evolving lineage (SEL). Fermentations with yeasts of FEL showed increased amounts of ethyl acetate, whereas yeasts belonging to SEL revealed no meaningful difference compared to the pure S. cerevisiae fermentation. Furthermore, co-fermentations resulted in lactic acid depletion (H. osmophila), extremely high isoamyl acetate levels (H. guilliermondii), reduction in glycerol (H. occidentalis), increased terpenols (H. opuntiae) as well as esterified terpenes (H. guilliermondii and H. uvarum). This is the first study to investigate the use of H. nectarophila and H. meyerii in relation to wine, of which fermentations using H. nectarophila revealed high levels of acetate esters. Nitrogen sources in form of amino acids have a major impact on the resulting aroma-production profile of yeasts as they serve as backbones for several volatile organic compounds. I explored amino acid uptake preferences of Hanseniaspora spp. of both lineages (H. uvarum = FEL; H. osmophila = SEL), S. cerevisiae (all glucophilic), as well as the fructophilic yeasts Starmerella bacillaris and Zygosaccharomyces rouxii in synthetic must, spiked with single amino acids. Among yeasts investigated, H. uvarum showed the most rapid amino acid uptake. Additional research on yeast fermentations with synthetic must supplemented with an amino acid mix resulted in amino acid-dependent synthesis of specific aroma compounds by the respective yeast. This study reveals similarities in both preferences in amino acid uptake and nitrogen source depending aroma compound synthesis of H. osmophila and S. cerevisiae. I investigated the transcriptomic profile of H. uvarum and S. cerevisiae to gain insight into the different regulation mechanisms involved in the synthesis of aroma compounds. Furthermore, I explored the impact of different levels of nitrogen (nitrogen deficiency/ diammonium hydrogen phosphate (DAHP) supplemented must) within the grape must on the gene expression profile and therefore on the resulting aroma profile. Even though the different nitrogen regimes did not significantly affect transcriptional levels, a major impact on both fermentation kinetics and the aroma profile could be monitored. H. uvarum unravelled possessing additional genes including alcohol acetyltransferase activity leading to a rapid esterification of higher alcohols to acetate esters. In addition, the lack of genes involved in the synthesis of higher alcohols and ethyl esters, as well as an up-regulation of genes responsible for the synthesis of acetyl-coA and acetate esters favour the high acetate ester production. In this study, I developed the first genetic modification tool for H. uvarum by constructing a synthetic marker gene encoding the hygromycin marker under the control of a H. uvarum promoter, flanked by ~1 000 bp homology region to the target locus, enabling the knock-out of one copy of the alcohol acetyltransferase 1 (ATF1) gene. By increasing the concentration of the antibiotic during selection, I could identify a knock-out of both ATF1 alleles in the diploid yeast, generating a homozygotic atf1 mutant. Fermentations resulted in a significant reduction of the acetate ester synthesis, proving the function of ATF1 as an important gene involved in the ester synthesis in H. uvarum. Genetic modification of H. uvarum was optimized by establishing a rapid PCR-based gene targeting approach for one-step gene replacement. Generation of two novel synthetic antibiotic resistance genes (pFA-hygXL and pFA-clnXL) provided resistance against hygromycin and nourseothricin, respectively. Short flanking-homology regions of 56-80 bp added to these selection markers via PCR enabled gene targeting and the deletion of both the H. uvarum LEU2 and LYS2 genes via two rounds of consecutive transformations, generating a leucine auxotrophic leu2/leu2 mutant and a lysine auxotrophic lys2/lys2 mutant, respectively. The genetic modification approach of H. uvarum using PCR-based gene targeting was further validated by targeted complementation of the auxotrophic leu2/leu2 strain.}, language = {en} } @phdthesis{Wersebeckmann2024, author = {Wersebeckmann, Vera}, title = {Terracing in steep slope viticulture and its potential to promote biodiversity in vineyard ecosystems}, volume = {2024}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-760}, school = {Hochschule Geisenheim University}, pages = {212}, year = {2024}, abstract = {A substantial area of the terrestrial surface is used for agricultural production. In Europe, many farmland species and ecosystems have evolved with traditional agricultural practices and rely on extensive cultivation for their survival. Today, agrobiodiversity is threatened by the abandonment of traditional agricultural land use. The cultivation of wine is one of the oldest forms of agriculture. On steep slopes, viticulture has shaped landscapes, cultural traditions, and unique ecosystems in many regions. In Germany, steep slope viticulture has been declining dramatically in recent decades due to insufficient profitability. The abandonment of these traditional cultural landscapes threatens the cultural heritage and the flora and fauna adapted to viticultural management. One solution to halt the decline of steep slope viticulture could be a change of cultivation system from vertically oriented rows to modern terraced vineyards. Here, the rows run parallel to the hillside, facilitating cultivation, and thus reducing production costs. At the same time, a large portion of terraced vineyard consists of uncultivated embankments, which can provide valuable habitats within the agricultural system. However, little is known about the effects of a cultivation system change and vineyard abandonment on biodiversity. In addition, information on how to sustainably revegetate terrace embankments is missing. Within the framework of this dissertation, the overall aim was to evaluate the potential of terraced vineyards to promote biodiversity and investigate measures for sustainable revegetation of terrace embankments. In addition, the effects of distinct vineyard management (vertically oriented vs. terraced) and vineyard abandonment on biodiversity were assessed. The main part of this thesis is based on a field study comparing three vineyard types (vertically oriented vineyard, terraced vineyard, abandoned vineyard) that were arranged in 15 triplets along the Upper Middle Rhine Valley (UMRV) in Germany. The effects of vineyard types, local vineyard parameters, and landscape structure on biodiversity were evaluated using four species groups. Studied groups represented plants and arthropod species (grasshoppers, wild bees, spiders). In a second field study, three newly constructed terrace embankments were revegetated using different seeding techniques and seed mixtures. In addition, measures to support plant establishment were evaluated. Plant establishment was assessed for three consecutive years in permanent vegetation plots. The first study on the three vineyard types revealed that there was no uniform positive effect of one vineyard type on all investigated groups. Instead, the responses were group and taxon-specific and driven by management-related disturbance intensities, local vegetation structures, soil and landscape structure. In total, the heterogeneous landscape and small-structured vineyard agroecosystem of the UMRV supported high species diversity, hosted high numbers of rare and threatened species, and diverse species communities across vineyard types. Plant species richness was enhanced by vineyard management and particularly benefited from terraced vineyards and rather nutrient-poor and extensively managed embankments. In comparison, plant communities of fallows were completely different with lower plant diversity. Grasshoppers were supported by vineyard management, and bare ground in vineyard inter-rows supported heat- and open-adapted species. Taller vegetation stands on terrace embankments enhanced grasshopper species richness while woody structures and vineyard abandonment reduced grasshopper diversity and abundance at the local and landscape scale. Wild bee species richness and abundance were strongly determined by their nesting needs. For ground-nesting bees, the suitability of soils for nesting was important, irrespective of vineyard management types whereas above-ground nesting bees were enhanced by woody structures of fallows at the local and landscape scale. Moreover, fallows further provided valuable floral and non-floral resources for both ground- and above-ground nesting bees. For spiders, there was no difference in species richness and abundance between vineyard types but many xerophilic species adapted to open habitat structures prevailed in terraced vineyards. Vineyard fallows supported highly distinct spider communities, including some late-successional species. In conclusion, the vineyard cultural landscape of the UMRV with both actively managed and abandoned vineyards led to a high diversity of plant and arthropod communities. Hence, for its preservation, a spatially heterogeneous landscape comprising both (semi) natural and viticultural-management elements is important. Results from the second study showed that terraced vineyards and especially terrace embankments can contribute to promoting biodiversity, especially if they are revegetated with regional seed mixtures. Seeds of locally adapted populations and hydro-seeding provided higher vegetation cover which is needed to prevent severe erosion whilst non-locally adapted standard seed mixtures and manual seeding had a higher failure risk and were more prone to severe precipitation events. Taken together, vineyard terracing appears to be a win-win solution for both winegrowers and biodiversity and thus helps to maintain viticulture on steep slopes.}, language = {en} } @phdthesis{Muschkullus2023, author = {Muschkullus, Thomas}, title = {Umgang mit der Komplexit{\"a}t naturschutzrelevanter Großprojekte}, volume = {2023}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, isbn = {13978-3-934742-90-1}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-664}, school = {Hochschule Geisenheim University}, pages = {507}, year = {2023}, abstract = {Großprojekte der Verkehrsinfrastruktur sind komplex und beeinflussen Schutzg{\"u}ter in hohem Maße; sie besitzen somit in aller Regel eine starke Relevanz f{\"u}r Ziele des Naturschutzes. Die Komplexit{\"a}t hat zur Folge, dass planerische Entscheidungen unter hohen Risiken und nicht dergestalt abgewogen werden, wie dies u.a. gem{\"a}ß dem Gesetz {\"u}ber die Umweltvertr{\"a}glichkeitspr{\"u}fung (UVPG) erforderlich ist. Die vorliegende Dissertation geht der Frage nach, wie mit dieser Komplexit{\"a}t umgegangen werden kann, um den Erfolg der Vorhaben zu optimieren.}, language = {de} } @phdthesis{Strack2022, author = {Strack, Timo}, title = {Comparison of terraced and steep slope vineyards emphasizing the impact of an altered viticultural system regarding physiology, health status and distinctive berry quality parameters of the grapevine}, volume = {2023}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-731}, school = {Hochschule Geisenheim University}, pages = {I -- 93}, year = {2022}, abstract = {In der Vergangenheit trugen Weine aus Steilstlagen zu einem maßgeblichen Teil zur Reputation deutscher Spitzenweine im nationalen und internationalen Vertrieb bei. Die historischen Weinlagen pr{\"a}gten die Kulturlandschaft und deren Entwicklung. Der deutsche Steillagenweinbau steht jedoch vor großen Herausforderungen. Bereits in den letzten Jahrzehnten wurde die Bewirtschaftung eines großen Teils steiler Weinbergsfl{\"a}chen aufgegeben. Die Gr{\"u}nde hierf{\"u}r sind vielf{\"a}ltig. Die im Vergleich zu direktzugf{\"a}higen Weinbergen in der Ebene kostenaufwendigere Kultivierung von Steillagen geht mit einer h{\"o}heren k{\"o}rperlichen Belastung und einem zus{\"a}tzlich h{\"o}heren Unfallrisiko einher. F{\"u}r viele Nachwuchskr{\"a}fte ist die Arbeit im Steillagenweinberg daher wenig attraktiv; f{\"u}r viele praktizierende Betriebe zu teuer. Doch auch der allgegenw{\"a}rtige Klimawandel wirkt auf die flachgr{\"u}ndigen Steillagen mit geringen Bodenauflagen unter zuk{\"u}nftig l{\"a}nger andauernden Trockenperioden, einer h{\"o}heren Verdunstung und generell unregelm{\"a}ßigeren, jedoch h{\"a}ufiger werdenden Starkniederschlagsereignissen, negativ auf die Ertragsstabilit{\"a}t und die allgemeine Traubenqualit{\"a}t ein. Dies betrifft vor allem die stark sonnenexponierten, flachgr{\"u}ndigen S{\"u}dh{\"a}nge steiler Weinbergslagen. Die moderne Querterrassierung von Weinbergen stellt eine m{\"o}gliche Alternative zur gegenw{\"a}rtigen Bewirtschaftung von Reben in der Falllinie dar. Die hangparallele Zeilenf{\"u}hrung auf Terrassenplattformen l{\"a}sst nicht nur einen h{\"o}heren Grad der Weinbergsmechanisierung zu. Die ebenen Terrassenfl{\"a}chen k{\"o}nnen den Oberfl{\"a}chenabfluss verringern und erlauben eine h{\"o}here Infiltration von Niederschl{\"a}gen, so dass eine Abschwemmung des fruchtbaren Weinbergsbodens reduziert oder verhindert und das Wasser im Boden besser zur{\"u}ckgehalten werden kann. In der vorliegenden Arbeit wurde untersucht welche Auswirkungen die Umstrukturierung von Falllinienweinbergen zu hangparallel verlaufenden Querterrassen auf mikroklimatische Parameter, die Bodenwasserdynamik und letztlich auf die vegetative und generative Leistung der Rebe hat. Die bis zu sieben untersuchten Weinbergspaare, bestehend aus Falllinienweinberg und Querterrasse, wurden entlang des unteren Rheingaus und des oberen Mittelrheintals hinsichtlich ihrer r{\"a}umlichen N{\"a}he zueinander und der Vergleichbarkeit des Pflanzguts untereinander ausgew{\"a}hlt und {\"u}ber einen Zeitraum von zwei bis vier Jahren begleitet. Es konnte gezeigt werden, dass eine durch die Weinbergstransformation orthogonal zur urspr{\"u}nglich in Falllinie verlaufenden Zeilenorientierung in einer Ver{\"a}nderung der Strahlungsverteilung und des W{\"a}rmehaushalts resultiert. Querterrassen konnten Wetterextreme abschw{\"a}chen und bewiesen eine f{\"u}r den Reifeabschluss beg{\"u}nstigte Besonnung der Traubenzone. Dies zeigte sich deutlich in der Unterscheidbarkeit der Gehalte qualit{\"a}tsbestimmender Traubeninhaltsstoffe, wie zum Beispiel Polyphenole und Aminos{\"a}uren. J{\"u}ngere Reben, die am {\"a}ußeren Ende der Terrassenplattform gepflanzt wurden, wiesen {\"u}ber alle Versuchsjahre hinweg hohe Trockenstressreaktionen auf. Dies milderte sich jedoch mit fortschreitendem Rebalter ab. Die Querterrassierung von Steillagenweinbergen erwies sich als probates Mittel zur Erzeugung hochwertigen Traubenmaterials. Zudem erg{\"a}nzt das Potential zur F{\"o}rderung der Artenvielfalt durch eine nachhaltige Bewirtschaftung der Terrassenb{\"o}schungen die als insgesamt positiv zu wertenden Versuchsergebnisse der vorliegenden Arbeit. Einzig die Herausforderung der z{\"u}gigen Etablierung bzw. Konkurrenzf{\"a}higkeit von Jungreben im Steillagenweinberg stellt nach wie vor eine Schwierigkeit dar, die es mit weinbaulichen, technischen oder z{\"u}chterischen Maßnahmen zu l{\"o}sen gilt.}, language = {en} } @phdthesis{Cotea2022, author = {Cotea, Victor}, title = {The removal of volatile phenols from Brettanomyces-contaminated wine using Molecularly Imprinted Polymers}, volume = {2022}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim, Deutschland}, isbn = {13 978-3-934742-89-5}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-747}, school = {Hochschule Geisenheim University}, pages = {I -- 239}, year = {2022}, abstract = {Brettanomyces infections represent one of the major red wine quality spoilers affecting the industry worldwide and will most likely continue to be so in the years to come. When attempting to correct or "cure" a Brettanomyces tainted wine, the most problematic metabolites to be removed are volatile phenols, particularly 4-ethylphenol. Molecular imprinting represents one of the technologies which promise to bridge the gap between the precision and selectivity of chemical analytical methods for investigating liquid matrices, and that of industrial filtration and separation technologies currently in use. In this work, the removal of 4-ethylphenol from wine with the aid of molecularly imprinted polymers was studied. Overall, the materials investigated in this work show promise when investigated in lab-scale conditions with model solutions. They can be effective in treating wine if the treatment conditions are appropriate and involve multiple regeneration steps.}, language = {en} } @phdthesis{Blois2023, author = {Blois, Louis}, title = {Genetic architecture of root related traits and scion respones induced by grapevine rootstock. First study in a monospecies population of Vitis berlandieri}, volume = {2023}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-676}, school = {Hochschule Geisenheim University}, pages = {3 -- 249}, year = {2023}, abstract = {In the context of climate change, crop adaptation is of major interest. Adaptation can be achieved by modifying cultural practices, field management, or plant material. In grafted plants, the plant material can be improved by the scion or the rootstock. The rootstock comprises the anchorage and the nutrient and water absorption as well as hormone signaling, which are closely involved in plant adaptation to its environment. Moreover, the interactions between the scion and the rootstock provides a broad range regarding adaptation strategies to different growing conditions and production aims. In vineyards, the most commonly rootstocks are hybrid breeds between American Vitis species (V. berlandieri, V. riparia, and V. rupestris) and sometimes V. vinifera. Despite recent findings revealing a large genetic diversity in these genetic backgrounds, rootstocks remain poorly studied, especially at the genetic level. The V. berlandieri hybrids have shown good performances in water deficit and limestone tolerance in vineyards. A selection of 286 V. berlandieri genotypes were chosen from a field-grown population of plants obtained from seedlings at Hochschule Geisenheim University, Germany. The samples were analysed regarding their genetic structure, which revealed two subpopulations and an association between the climatic conditions of the sampling areas and their genetic variability. While an isolation by distance has been highlighted, it was not possible to detect the variability in the genetic burden of the two subpopulations. This population was used for grafting of V. vinifera cv. Riesling (clone 24-209Gm), which was planted in pots and grown in the greenhouse fortwo consecutive years with no limiting conditions. A root phenotyping has been carried out after one year of growing, revealing a high variability at the phenotype and genetic level. The heritability was high for these traits which allowed to carry out a genome wide association study and to detect eleven genetic markers associated with root-related traits. Each year, the population was planted in a field experiment in order to observe the variability of conferred traits induced by the rootstock to the scion. A medium to high variability has been detected for the pruning weight and the δ13C as well as a medium to high heritability. A genome wide association study has allowed us to detect two significant markers for δ13C but no markers were highlighted for the pruning weight. Correlations between root-related and scion conferred traits have been found. A comparison of the phenotypical performance of the V. berlandieri genotypes to commercial rootstocks, i.e. SO4, 110R, B{\"o}rner and 5BB, resulted in interesting insights for the selection of futuregenotypes for rootstock breeding. This association study is the first carried out in a natural population of a wild Vitis monospecies and highlights new opportunities for grapevine rootstocks breeding.}, language = {en} } @phdthesis{Kahn2023, author = {Kahn, C{\´e}cile}, title = {Study of the impact of atmospheric CO2 level on grapevine leaf physiology, berry maturation and composition at harvest, using a FACE (Free Air Carbon dioxide Enrichment) system}, volume = {2023}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-724}, school = {Hochschule Geisenheim University}, pages = {205}, year = {2023}, abstract = {Climate change cannot currently be ignored and impacts all fields of agriculture. IPCC reports forecast an increase of up to 700 ppm of atmospheric carbon dioxide concentration at the end of the 21st century. Parameters such as elevated global temperature, reduced precipitations in certain areas of the world and increase of atmospheric carbon dioxide concentration are modifying plants' environment. Grapevine, which is a crop of economic and cultural importance, is very sensitive to climate modifications. The effects of temperature or water stress on grapevine has been widely investigated, and elevated carbon dioxide has been mainly studied in enclosed systems such as greenhouses. However, the impact of increased concentration of carbon dioxide on plants in open-field experiments remains scarcely studied because of the technical challenge that it represents. In this context, the aim of this PhD work was to investigate the impact of elevated carbon dioxide concentration using the set-up VineyardFACE located at Geisenheim University. This open field set-up enables to apply a moderate and gradual increase (+20\%) of ambient carbon dioxide concentration on two grapevine cultivars, Riesling, and Cabernet Sauvignon. While knowing the impact of elevated carbon dioxide treatment on leaf physiology and vegetative growth from previous studies (Wohlfahrt et al., 2018), as well as on berry composition during the early years of fumigation, the goal of this study was to determine the effects of elevated carbon dioxide treatment on agronomical traits, primary metabolites (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins, terpenes) on vines undergoing six years of fumigation, as well as monitoring berry development and following berry ripening for successive seasons. Intermediates from central metabolism were also studied for two years (2020 and 2021), and terpene analysis was realized on Riesling must 2021. Our results showed that although photosynthesis was still enhanced, little effects were found of elevated carbon dioxide treatment on primary metabolites as well as on berry ripening rates, for successive seasons for both Riesling and Cabernet Sauvignon. However, a trend of reduced total anthocyanins concentration in Cabernet Sauvignon was demonstrated by elevated carbon dioxide treatment mainly in 2020, while anthocyanins composition remained fairly similar. Terpenes (both bound and free) composition in Riesling in 2021 was not impacted by elevated carbon dioxide treatment.}, language = {en} } @phdthesis{Schlering2022, author = {Schlering, Christine}, title = {Chemical composition of field grown vegetables as influenced by season and moderately reduced water supply}, volume = {2022}, edition = {1. Auflage}, publisher = {Shaker-Verlag}, address = {D{\"u}ren}, isbn = {978-3-8440-8457-3}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-393}, school = {Hochschule Geisenheim University}, pages = {171}, year = {2022}, abstract = {In this doctoral thesis, the effects of moderately reduced water supply and seasonal variations was studied regarding the chemical and nutritionally relevant composition of the edible harvest organs of three different vegetable crops, i.e. cucumber fruit (Cucumis sativus L.), radish roots (Raphanus sativus L. var. sativus), and spinach leaves (Spinacia oleracea L.). The study was conducted to demonstrate putative plant-physiological alterations in their chemical composition that may be evoked by moderate water deficits during cultivation under open field conditions. The vegetable crops were selected according to differing harvest organs (leaves, roots and fruit), being cultivated during three consecutive years under open field conditions and two different water supply treatments within a randomized block design with multiple sets of six plots each. Depending on the vegetable, the provided water amount of the moderately reduced water supply treatment varied between 80-97\% of the well-watered control treatment. Chapter 1 dealt with the effects of moderate water reduction of 3-20\% on radish. Including one cultivation set per year and an additional set in 2016, i.e. a total of four separate sets, a dry matter-based increase of myo-inositol was observed, whereas the levels of selected minerals and trace elements like iron and manganese as well as those of phenolic compounds and glucosinolates decreased or remained unchanged upon moderately reduced water supply. Only insignificant effects of reduced water supply were seen on the levels of acylated anthocyanins, which represent a highly important commercial quality trait due to their importance for the roots' or hypocotyls' color. In contrast, the levels of fresh matter-related analytes were mainly enhanced by reduced water supply due to higher contents of dry matter. Thus, the overall quality of radish tubers seemed to be only marginally affected by moderate water limitation. Similar results were observed for spinach as presented in Chapter 2. Nevertheless, reducing the total water amount by only 4-10\% during cultivation led to various significant alterations in the chemical composition of the leaves. Similar to radish, higher dry matter-based levels of myo-inositol were found in spinach grown under low water reduction. Moreover, increased contents of zinc and manganese were found, while the levels of malic acid, fumaric acid, phosphate and chloride decreased upon slight water reduction in spinach dry matter. In contrast, spinach fresh matter was expectedly characterized by significantly higher contents of polyols, ascorbic acid, potassium, nitrogen, phosphorous, zinc and manganese, as well as total flavonoids and carotenoids, including nutritionally highly relevant compounds like the provitamin A-active β-carotene and the macular pigment lutein. Noteworthy, strong seasonal variations have been observed for numerous minor phytochemicals, such as for example for a series of specific flavonoids, whose contents seemed to be dependent on the respective irradiation conditions of the cultivation set. In contrast to radish and spinach, cucumber from open field cultivation reacted differently to slightly reduced water supply, as summarized in Chapter 3. When cucumber fruits obtained from plants received 85-90\% of the total water amount of the control treatment, they exhibited significantly higher levels of malic acid, calcium, and magnesium, while those of phosphate, phosphorous, nitrogen, and iron decreased based on dry matter. Fruit dry matter-content did not significantly change due to moderate water restriction, and, as a result, the concentration of most analytes tended to decrease in the cucumber fresh matter when grown under reduced water supply. The chemical analyses of single cucumber fruit compartments (exocarp, mesocarp and endocarp) from fruits grown under 60\% of the full supply in a separate greenhouse experiment confirmed that malic acid, certain minerals and trace elements, as well as carotenoids like the most abundant lutein were relatively sensitive to moderate water reduction. Altogether, a moderately reduced water supply was shown to significantly alter the chemical composition of the aforementioned vegetable crops. Considering the broad range of analytes from, e.g., minerals and anions to polyols and acids to micronutrients like provitamin A, it became clear that water supply reduction as studied herein did not lead to generalizable effects such as an undesired decrease or a desired enhancement of valuable compounds. For instance, the levels of selected health-promoting constituents in the fresh matter of radish and spinach were increased, while those of the same compounds contained in cucumber did not benefit at all. Generally, the overall quality of vegetables was clearly shown to be influenced not only by water supply, but also by the interaction with other abiotic factors, especially when cultivation took place in open field. Further study in the future should target interactions of moderately reduced water supply situations with changes in other abiotic factors, such as elevated CO2 concentrations.}, language = {en} } @phdthesis{Biegert2023, author = {Biegert, Konni}, title = {"Smart Horticulture: Application of sensors and modelling to predict fruit growth, quality and storage behaviour of 'Braeburn' apples"}, volume = {2023}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-710}, school = {Hochschule Geisenheim University}, pages = {151}, year = {2023}, abstract = {Physiologische Lagerkrankheiten verursachen weltweit betr{\"a}chtliche wirtschaftliche Verluste bei einer Reihe von kommerziell wichtigen Kernobstsorten. Bei gleichen Lagerungsbedingungen bei derselben Sorte kann das Auftreten und die H{\"a}ufigkeit der Krankheiten in verschiedenen Jahren in einer Weise variieren, die durch eine Interaktion von Vorernte- und Nacherntefaktoren erkl{\"a}rt werden muss. Wesentliche bekannte Einflussgr{\"o}ßen sind Jahreswetterverlauf, Management in der Obstanlage, wie z.B. Blatt-Frucht Verh{\"a}ltnis, Calciumgehalt in den Fr{\"u}chten sowie Erntetermin und Lagerungsbedingungen. Bislang kann das Auftreten der Krankheiten jedoch nicht sicher vorhergesagt werden, um dadurch das Management in der Obstanlage oder im Lager entsprechend anzupassen. Analysen großer Datenmengen mithilfe K{\"u}nstlicher Intelligenz (KI) bieten neue M{\"o}glichkeiten unterschiedliche Datenarten und -s{\"a}tze zu verkn{\"u}pfen. Das Ziel der vorliegenden Arbeit ist die kleinr{\"a}umig und nicht-destruktive {\"U}berwachung der Fruchtentwicklung in der Obstanlage mit den oben genannten Managementmaßnahmen. KI Prognosemodelle wurden f{\"u}r die Sorte 'Braeburn' erstellt. 'Braeburn' ist anf{\"a}llig f{\"u}r physiologische Lagerkrankheiten, bei der im Fruchtfleisch oder unter der Schale Verbr{\"a}unungen auftreten. Mit zeltartigen Umbauungen {\"u}ber den Obstb{\"a}umen wurde die Temperatur in zwei fruchtphysiologisch wichtigen Perioden (Bl{\"u}tenblattabfall bis T-Stadium, drei Wochen vor der Ernte) erh{\"o}ht oder abgesenkt, um den Temperatureinfluss zu untersuchen. Unseres Wissens nach konnte dadurch zum ersten Mal in der Obstanlage {\"u}ber ausgewachsenen B{\"a}umen unterschiedliche Temperaturverl{\"a}ufe erzeugt werden. Dabei wurde ein positiver Einfluss auf die Reduzierung von inneren Verbr{\"a}unungen durch warme Nachttemperaturen (>10°C) vor der Ernte festgestellt. Insgesamt zeigte jedes Versuchsjahr unterschiedliche Auspr{\"a}gungen der physiologischen Fruchterkrankungen. Managementmaßnahmen und Witterungsbedingungen f{\"u}hrten zu signifikant unterschiedlichen Fruchtwachstumsverl{\"a}ufen und optischer nicht-destruktiver Punktspektroskopie. Die zweiw{\"o}chentlich wiederholten Spektroskopiemessungen an den gleichen markierten Fr{\"u}chten und deren Weiterverarbeitung in Partial Least Square Regression (PLSR) Modellen wurden einerseits auf ihre Genauigkeit {\"u}berpr{\"u}ft und zus{\"a}tzlich mit Modellen und Wetterdaten deren zuk{\"u}nftige Zust{\"a}nde vorhergesagt. Die statistische Auswertung der dreij{\"a}hrigen Daten zur n{\"o}tigen Probenanzahl und Fehler bei der destruktiven Trockensubstanz (TS) Analyse resultierte in Probenanzahlen von 100 St{\"u}ck pro Jahr, die eine Bandbreite von niedrigen bis hohen TS Werten umfassen m{\"u}ssen. Ein unbalancierter Laborfehler von 0.1-1 °Brix hat keinen Einfluss auf die modellierten TS Werte. Im Vergleich zur destruktiven TS Bestimmung im Labor konnte die Spektroskopie die TS im Mittel mit einer Abweichung von 0.5 °Brix bestimmen. Spektralmessungen in der Obstanlage nach einem Regenereignis f{\"u}hrten dabei zu keiner Ver{\"a}nderung im sichtbaren Spektralbereich. Jedoch k{\"o}nnen Kulturabdeckungen wie z.B. Regenschutzfolien {\"u}ber den Obstb{\"a}ume zu geringeren Wasserabsorptionswerten bei 975\,nm f{\"u}hren. Die Bereitststellung der Daten auf Baumsektor Ebene wurde in dieser Arbeit manuell durchgef{\"u}hrt. Jedoch wurden erste Schritte unternommen, um Fruchtwachstums- und Spektroskopiedaten per GPS Signal innerhalb einer Karte darzustellen. Die kleinr{\"a}umige Datenaufnahme auf Baumsektor Ebene ergaben f{\"u}r TS, Chlorophyll und Anthocyan Indexberechnungen, sowie auch f{\"u}r physiologische Krankheiten deutliche Unterschiede. Bei zuk{\"u}nftigen Forschungsarbeiten und Entscheidungsmodellierungen sollte dies ber{\"u}cksichtigt werden, auch wenn dies unter den gegebenen Umst{\"a}nden noch nicht voll-automatisiert umsetzbar ist. Das Prognosemodell zur Entstehung von physiologischen Krankheiten (Kernhausbr{\"a}une, Kavernen) konnte mit zweij{\"a}hrigen Daten die Entstehung der Lagerkrankheiten nach der Auslagerung und die Fruchtfleischfestigkeit zur Ernte in 90 \% der F{\"a}lle richtig vorhersagen. Somit konnte gezeigt werden, dass eine kleinr{\"a}umige Datenerhebung auf Baumsektor Ebene zur Prognose von physiologischen Lagerkrankheiten mithilfe KI Modellierungen angewendet werden kann. Weitere Forschungsarbeiten mit nicht-destruktiven Fruchtmessungen in der Obstanlage und dem Einfluss von Wetterbedingungen werden weitere Einblicke zur Qualit{\"a}tsverbesserung von {\"A}pfeln erm{\"o}glichen.}, language = {en} } @phdthesis{Mengel2023, author = {Mengel, Fabian}, title = {Kosten- und Margenstrukturen von Weing{\"u}tern}, volume = {2023}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-630}, school = {Hochschule Geisenheim University}, pages = {338}, year = {2023}, abstract = {Im Rahmen dieser Arbeit wurde ein Modell zur Kosten- und Margenanalyse deutscher Weing{\"u}ter entwickelt und angewendet, mit dem die Kosten- und Margenstrukturen deutscher Weing{\"u}ter systematisch und umfassend sowie auf der Grundlage empirischer Betriebsdaten bis auf die Ebene der einzelnen Kostentr{\"a}ger (Weine) und Absatzsegmente (Kundengruppen) der Weing{\"u}ter analysiert wurden. Aus der Sicht der Forschung schließt diese Arbeit eine Forschungsl{\"u}cke, denn die Kosten- und Margenstrukturen sowie die wesentlichen Kostentreiber deutscher Weing{\"u}ter wurden in dieser Arbeit erstmals betriebs{\"u}bergreifend auf der Ebene differenzierter Kostentr{\"a}ger (Weine) und Absatzsegmente (Kundengruppen) sowie auf der Grundlage empirischer Betriebsdaten mit wissenschaftlichen Methoden analysiert. Den untersuchten Weing{\"u}tern wurden die Analysen auf einzelbetrieblicher Ebene zur Verf{\"u}gung gestellt. Damit erhalten die Weing{\"u}ter Informationen {\"u}ber die H{\"o}he und die Zusammensetzung der Herstellungskosten ihrer einzelnen Weine, {\"u}ber die Vertriebskosten sowie {\"u}ber die Margen der Weine unter Ber{\"u}cksichtigung der verschiedenen Absatzsegmente. F{\"u}r die Weing{\"u}ter wird dadurch ersichtlich, welche Weine und welche Absatzsegmente zum betrieblichen Erfolg beitragen und in welchen Bereichen Handlungsbedarf besteht. Basierend auf der Wertsch{\"o}pfungskette der Weinproduktion und -vermarktung wurden dazu zun{\"a}chst die Betriebsbereiche der Weing{\"u}ter voneinander abgegrenzt und es wurden spezielle Anforderungen dieser Betriebsbereiche an die Entwicklung und Umsetzung des KMA-Modells f{\"u}r Weing{\"u}ter definiert. Aufbauend auf diesen Anforderungen wurde ein Grundkonzept des standardisiert anwendbaren KMA-Modells entwickelt und vorgestellt. Das KMA-Modell umfasst einerseits einen Input-Bereich, in den die betriebsspezifischen Aufwendungen der Gewinn- und Verlustrechnung sowie das betriebsspezifische Anlageverm{\"o}gen der Weing{\"u}ter {\"u}bernommen werden. Dar{\"u}ber hinaus erforderliche Daten zur Kosten- und Margenanalyse werden {\"u}ber ein betriebsspezifisches Erhebungsblatt (eine MS Excel Tabelle) auf einzelbetrieblicher Ebene erfasst und in das KMA-Modell als Input {\"u}berf{\"u}hrt. Im Bereich der Berechnungen werden zun{\"a}chst neutrale Aufwendungen abgegrenzt und die Kostenarten der Weing{\"u}ter werden auf der Grundlage der Input-Daten ermittelt. Die Kostenarten werden dabei {\"u}ber mehrere Ebenen nach den Betriebsbereichen Weinbau, Kellerwirtschaft, Verwaltung, Vertrieb und Sonstiges untergliedert. Das Ergebnis der Kostenartenrechnung sind pagatorische (aufwandsgleiche) und wertm{\"a}ßige (kalkulatorische) Kosten von Weing{\"u}tern, denen spezifische Ressourcen zur verursachungsgerechten Kostenverrechnung zugeordnet werden. Der Kern des KMA-Modells ist die verursachungsgerechte Kostenverrechnung der Teilbereiche Weinbau, Kellerwirtschaft, Verwaltung, Vertrieb und Sonstiges. In den Bereichen Weinbau und Kellerwirtschaft werden im Rahmen der Verrechnungen zun{\"a}chst Kostentr{\"a}ger-Einzelkosten auf die Kostentr{\"a}ger (Weine) zugeordnet. Im Bereich Weinbau sind dies i.W. Pacht- und Pachtbewirtschaftungskosten f{\"u}r bestimmte Weinberge, Kapitalkosten f{\"u}r den Grund und Boden der Weinberge sowie Abschreibungen und Kapitalkosten f{\"u}r die Rebanlagen der Weinberge, welche nach verschiedenen Bewirtschaftungs- und Erziehungsformen differenziert verrechnet werden. Als kellerwirtschaftliche Kostentr{\"a}ger-Einzelkosten werden insb. Kosten f{\"u}r den Zukauf von Trauben, Most und/oder Fasswein, Kosten f{\"u}r die Flaschenausstattung (Kosten f{\"u}r die Flasche, den Verschluss, das Etikett, ggf. eine Zusatzausstattung und die Verpackung) sowie Kapitalkosten f{\"u}r das in den produzierten Weinen gebundene Kapital bis zum Verkauf der Weine verrechnet. Im darauffolgenden Schritt werden die Kostentr{\"a}ger-Gemeinkosten {\"u}ber ressourcenspezifische Kostentreiber aufgespalten und nach Prozessen sowie Aktivit{\"a}ten verrechnet. Im Bereich Weinbau werden diese Verrechnungen nach Bewirtschaftungs- und Erziehungsformen und im Bereich Kellerwirtschaft nach Gebindearten und -gr{\"o}ßen w{\"a}hrend des Weinausbaus der Kostentr{\"a}ger (Weine) differenziert. Bei den Verrechnungen {\"u}ber die Prozesse und Aktivit{\"a}ten wird eine Vielzahl an Kostentreibern angewendet, damit modellseitig eine m{\"o}glichst verursachungsgerechte Kostenverrechnung sichergestellt wird. Im Bereich Weinbau sind dies bspw. die Arbeitskraftstunden je ha je Aktivit{\"a}t sowie die Maschinenstunden je ha je Aktivit{\"a}t in Abh{\"a}ngigkeit unterschiedlicher Bewirtschaftungs- und Erziehungsformen der Weinberge, die zur Erzeugung bestimmter Weine verwendet werden. Als Kostentreiber des Betriebsbereichs Kellerwirtschaft werden modellseitig i.W. die Kostentreiber Arbeitskraftstunden je 1.000 l je Aktivit{\"a}t sowie die ben{\"o}tigten Maschinenstunden je 1.000 l je Aktivit{\"a}t in Abh{\"a}ngigkeit unterschiedlicher Gebindearten und -gr{\"o}ßen w{\"a}hrend des Ausbaus der Weine angewendet. Bestimmte Kostenarten der Betriebsbereiche Weinbau und Kellerwirtschaft werden vereinfacht {\"u}ber sonstige Verrechnungen auf die Kostentr{\"a}ger (Weine) geschl{\"u}sselt. Auch f{\"u}r die Kostenverrechnungen des Betriebsbereichs Vertrieb werden ressourcenspezifische Kostentreiber zur verursachungsgerechten Schl{\"u}sselung der Vertriebskosten auf die Absatzsegmente des KMA-Modells angewendet. Dies sind u.a. erbrachte Arbeitskraftstunden der Arbeitskr{\"a}fte je Absatzsegment zur Schl{\"u}sselung der Personalvertriebskosten, verschiedene Versandarten und -mengen zur Schl{\"u}sselung der Versandkosten sowie fl{\"a}chenm{\"a}ßige Anteile der Nutzung von Geb{\"a}uden f{\"u}r vertriebliche Zwecke zur Schl{\"u}sselung von Geb{\"a}udekosten. Anschließend werden die Kosten der Absatzsegmente auf die Kostentr{\"a}ger (Weine) verrechnet, die {\"u}ber die jeweiligen Absatzsegmente verkauft werden. Die Kosten der Betriebsbereiche Verwaltung und Sonstiges werden vereinfacht {\"u}ber sonstige Verrechnungen auf die Kostentr{\"a}ger (Weine) geschl{\"u}sselt. Der letzte Berechnungsschritt des KMA-Modells ist die Margenkalkulation der Kostentr{\"a}ger (Weine) nach den Absatzsegmenten (Kundengruppen) des KMA-Modells. Dabei werden die Kostentr{\"a}ger-Selbstst{\"u}ckkosten der Weine unter Ber{\"u}cksichtigung der Absatzsegmente von den Verkaufspreisen der Kostentr{\"a}ger (Weine) je Absatzsegment subtrahiert. Die Anwendung des KMA-Modells in 22 deutschen Weing{\"u}tern zeigt, dass Personalkosten (33 \%), Materialkosten (23 \%) und Kapitalkosten (20 \%) in der Summe 76 \% der Gesamtkosten im Mittel der untersuchten Weing{\"u}ter ausmachen. Auf der Ebene der Betriebsbereiche (Kostenstellen) entfallen im Mittel der untersuchten Weing{\"u}ter zwei Drittel der Gesamtkosten auf die Betriebsbereiche Weinbau (37 \%) und Kellerwirtschaft (30 \%). 20 \% der Gesamtkosten entfallen auf weinbauliche Prozesse und Aktivit{\"a}ten sowie 14 \% der Gesamtkosten auf kellerwirtschaftliche Prozesse und Aktivit{\"a}ten. Die H{\"o}he der Prozesskosten je ha im Betriebsbereich Weinbau h{\"a}ngt wesentlich von den unterschiedlichen Bewirtschaftungs- und Erziehungsformen ab, in denen die Weine erzeugt werden. Wesentliche Treiber f{\"u}r die Unterschiede der weinbaulichen Prozesskosten je ha zwischen den Bewirtschaftungs- und Erziehungsformen sind die Prozesse Rebschnitt, Pflanzenschutz, Begr{\"u}nungsmanagement und Traubenlese. Je Liter betrachtet wirkt sich der Hektarertrag der Weine wesentlich auf die weinbaulichen Prozesskosten der Weine aus, denn die empirischen Untersuchungen dieser Arbeit ergeben, dass die weinbaulichen Prozesskosten der untersuchten Weine bei einer Steigerung des Hektarertrags um 1.000 l / ha um rd. 0,30 € / l abnehmen. Kellerwirtschaftliche Prozesskosten entfallen im Mittel der untersuchten Weing{\"u}ter gr{\"o}ßtenteils auf die Verarbeitungsstufe „Mostverarbeitung und Ausbau zum Jungwein". Die empirischen Untersuchungen zeigen, dass die kellerwirtschaftlichen Prozesskosten der Weine, welche in Barriquef{\"a}ssern ausgebaut werden, um rd. 2,34 € / l signifikant h{\"o}her ausfallen, als die kellerwirtschaftlichen Prozesskosten der Weine, welche in Edelstahltanks ausgebaut werden. Dar{\"u}ber hinaus hat die durchschnittliche Gebindegr{\"o}ße der Gebinde, in denen die Weine ausgebaut werden, einen signifikanten Einfluss auf die H{\"o}he der kellerwirtschaftlichen Prozesskosten der Weine. Aus den Untersuchungen geht hervor, dass die kellerwirtschaftlichen Prozesskosten der untersuchten Weine bei einer Erh{\"o}hung der durchschnittlichen Gebindegr{\"o}ße w{\"a}hrend des Weinausbaus um 1.000 l je Gebinde um 0,10 € / l abnehmen. Die H{\"o}he und die Zusammensetzung der Vertriebskosten der untersuchten Weing{\"u}ter h{\"a}ngt wesentlich von den Absatzsegmenten ab, {\"u}ber welche die Weine verkauft werden. Die Vertriebskosten der Absatzsegmente Privatkunden und Gastronomiekunden liegen im Mittel der Weing{\"u}ter mit 1,67 € / Fl. bzw. 0,92 € / Fl. {\"u}ber den Vertriebskosten der {\"u}brigen Absatzsegmente. Die Unterschiede der Vertriebskosten zwischen den Absatzsegmenten ergeben sich i.W. aus dem variierenden Einsatz von Personal, Werbe- und Versandmaßnahmen sowie Geb{\"a}uden in Abh{\"a}ngigkeit der Absatzsegmente. Im Rahmen der Arbeit wurden insgesamt 686 Kostentr{\"a}ger (Weine) mit dem KMA-Modell ausgewertet. Deskriptiv betrachtet zeigt sich dabei, dass relativ hochpreisige Weine im Vergleich zu relativ niedrigpreisigen Weinen im Mittel der untersuchten Weing{\"u}ter i.d.R. h{\"o}here Herstellungs- und Selbstkosten aufweisen. Trotz der h{\"o}heren Herstellungs- und Selbstkosten erzielen die relativ hochpreisigen Weine im Vergleich zu den relativ niedrigpreisigen Weinen in der Tendenz (deskriptiv betrachtet) allerdings h{\"o}here Margen je Liter sowie h{\"o}here prozentuale Margen auf Selbstkosten. Vor diesem Hintergrund wurden die Steigerungen der prozentualen Margen der Weine in Abh{\"a}ngigkeit der Verkaufspreise der Weine unter Ber{\"u}cksichtigung der unterschiedlichen Absatzsegmente detailliert in einem Regressionsmodell untersucht. Aus den Untersuchungen mit diesem Regressionsmodell geht hervor, dass die untersuchten Weine bei einem Verkauf {\"u}ber die Absatzsegmente Privatkunden und Gastronomiekunden mit einer Steigerung des Verkaufspreises um einen € je Liter um rd. 3,2 \% h{\"o}here Margen erzielen. Etwas geringer f{\"a}llt die Steigerung der Margen der Weine in Abh{\"a}ngigkeit der Verkaufspreise in den Absatzsegmenten Fachhandelskunden und Großhandelskunden aus, denn mit einer Steigerung des Verkaufspreises um einen € je Liter steigen die Margen der Weine im Vergleich zu den Absatzsegmenten Privatkunden und Gastronomiekunden nur um rd. 2,3 \% bzw. 2,6 \%. Die Margen der Weine mit einem Referenzpreis von 2 bis < 4 € / l liegen bei einem Verkauf {\"u}ber die Absatzsegmente Privat-, Gastronomie-, Fachhandels- und Großhandelskunden zwischen - 4 \% und 2 \%. Zusammenfassend und {\"u}berbetrieblich bleibt deshalb festzuhalten, dass Weine der untersuchten Weing{\"u}ter mit einem Referenzpreis von 2 bis < 4 € / l sowie darunter kaum vollkostendeckend sowie mit positiven Margen verkauft werden k{\"o}nnen.}, language = {de} } @phdthesis{Bitsch2021, author = {Bitsch, Linda}, title = {Interpersonal ties influencing strategic decisions regarding inter-firm partnerships}, volume = {2022}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, isbn = {13 978-3-934742-88-8}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-418}, school = {Hochschule Geisenheim University}, pages = {9 -- 371}, year = {2021}, abstract = {Interpersonal ties influencing strategic decisions regarding inter-firm partnerships The agri-food industries changed from vertically integrated supply chains towards vertical cooperating networks. In this context, inter-firm partnerships are seen as a possible tool to address changing markets and competition. Within strategic management, inter-firm partnerships are valued as a potential source of competitive advantage, which ascribes importance to the strategic management of partnerships. In the underlying classical cooperation theory, business cooperation decisions are assumed to be made rationally. Initial empirical studies show that managers have a personal influence on strategic decisions in business cooperation and that their decisions are not always in line with the common rationality assumptions in economics. Preliminary studies show initial "softer" or even "non-economic" interpersonal factors such as heuristics, biases, emotions, personality traits, or norms that can mitigate rationality and impact decisions in strategic collaborations made by managers. Human agents and their influence on strategic relationship management and intrafirm-, interfirm- and network-level outcomes are put into the research center of this study. Specifically, this thesis aims to explore whether managers (can) take an individual influence on strategic decision-making in B2B cooperation relations. Furthermore, it aims to analyze and identify which personal characteristics factors play a role during the decision-making process regarding inter-firm partnerships in the agri-food industry. First empirical studies have evidenced that interaction - or in other words, the influence of managers - is a critical process in developing strategic buyer-seller relationships in B2B relations. I have argued that personal characteristics exist, and they influence decisions in inter-firm cooperation. An additional level, namely the personal-level, has to be explicitly included in the strategic chain management framework. Four general research expectations on which personal characteristics influence decision-making in inter-firm partnerships were derived. As a consequence of the currently limited literature base I conducted two exploratory and qualitative studies in the form of expert interviews to first identify and prioritize the most critical driving personal influences on mangers in the German wine industry. Together, these two studies served as the basis for developing the research expectations and the main study in the form of factorial surveys. The study's statistical population size includes all companies that engage in grape-buying relationships (in Germany) to produce wine commercially (roughly 9,000 firms). The sample size based on the number of respondents is 203, but based on the judgments, the sample size is 602 judgments, as each respondent judged several items. After a descriptive statistical analysis, the Partial Least Squares (PLS) technique, in particular the multi-group analysis was used to evaluate the results. The most important finding is that managers' personal characteristics influence strategic decisions in chain management, particularly on mechanisms to manage cooperation. Furthermore, in this study, the characteristics of fairness, escalation of commitment, overconfidence, and representation heuristic significantly impacted some of the power and trust statements. Thus, focal firms have to consider and develop appropriate mechanisms to address and manage personal influences. Secondly, it was shown that various personal characteristics influence chain management decisions simultaneously and with different intensities in a positive or negative manner.}, language = {en} } @phdthesis{Obermair2023, author = {Obermair, Elisabeth}, title = {Logistics challenges in omni-channel grocery retailing}, volume = {2023}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-619}, school = {Hochschule Geisenheim University}, pages = {175}, year = {2023}, abstract = {Die vorliegende Dissertation besch{\"a}ftigt sich mit logistischen Problemstellungen im Lebens-mitteleinzelhandel, welche im Omni-Channel Kontext betrachtet werden. Der Omni-Channel Ansatz gewinnt an Bedeutung, da der Onlinehandel mit Lebensmittel kontinuierlich w{\"a}chst. Neben reinen Onlineh{\"a}ndlern, treten auch traditionell station{\"a}re H{\"a}ndler in den Onlinemarkt ein. Die Weiterentwicklung von bestehenden Strukturen hin zu einem Omni-Channel Konzept stellt eine komplexe Herausforderung dar, welche sich der erste Beitrag der Dissertation widmet. Als Basis dient eine Fallstudie mit europ{\"a}ischen Lebensmittelh{\"a}ndlern. Da unterschiedliche Konzepte in den L{\"a}ndern dominieren, werden deren jeweiligen Vorz{\"u}ge und Unterschiede heraus-gearbeitet. Im Fokus stehen die zentralen Komponenten eines Distributionsnetzwerkes, welche die Sortimentsbreite, das Kommissioniersystem und die Ausgestaltung der letzten Meile, hin-sichtlich Lieferart und -zeit, darstellen. Neben dem wachsenden Onlinegesch{\"a}ft ist eine feine Aussteuerung von logistischen Prozessen aufgrund von volatilen Nachfragen eine komplexe Aufgabe im Lebensmitteleinzelhandel. Eine immer wiederkehrende Problematik, welcher sich der zweite Beitrag widmet, sind Feiertage. Das Besch{\"a}ftigungsverbot an Feiertagen in Deutschland f{\"u}hrt dazu, dass H{\"a}ndler weniger Zeit zur Durchf{\"u}hrung der logistischen Prozesse haben. Zus{\"a}tzlich ist meist ein h{\"o}heres wochen-bezogenes Volumen als in Standardwochen zu bew{\"a}ltigen. Obwohl Feiertagswochen detailliert geplant werden, m{\"u}ssen viele Herausforderungen ad-hoc gel{\"o}st werden. Folglich liegt der Schwerpunkt der Analyse auf den operativen Planungsbereichen: der Disposition, der Lager-planung, der Transportplanung und dem Filialmanagement. Die Ergebnisse des zweiten Beitrags liefern potenzielle Handlungsweisen zur effizienten und effektiven Gestaltung der betrachteten Planungsbereichen. Der dritte Beitrag besch{\"a}ftigt sich mit den Herausforderungen der Covid-19 Pandemie f{\"u}r den deutschen Lebensmitteleinzelhandel. Im Gegensatz zu der Feiertagsproblematik, f{\"u}hrte der Ausbruch der Pandemie zu unerwarteten Nachfragespitzen und Unsicherheiten im Handel. Anhand eines explorativen Forschungsansatzes werden die Auswirkungen der Pandemie auf die Planungsbereiche der Beschaffung, der Lagerhaltung, der Disposition, dem Transport und dem Filialmanagement untersucht. Basierend auf einer zweij{\"a}hrigen Betrachtung werden zuk{\"u}nftige Entwicklungsfelder f{\"u}r den deutschen Lebensmitteleinzelhandel identifiziert. Sie zeigen auf, in welche Richtung logistische Prozesse weiterentwickelt werden k{\"o}nnten, um potenziellen zuk{\"u}nftigen Anforderungen der Branche begegnen zu k{\"o}nnen Die kumulative Dissertation umschließt die drei beschriebenen Studien, welche einen Beitrag zur qualitativen Forschung der Omni-Channel Handelslogistik leisten. Aktuelle Herausforderungen des Lebensmitteleinzelhandels werden aus europ{\"a}ischer, insbesondre deutscher Perspektive betrachtet. Die explorativ generierten Ergebnisse liefern Handlungsweisen f{\"u}r volatile und disruptive Zeiten sowie m{\"o}gliche Entwicklungsrichtungen f{\"u}r Lebensmittelh{\"a}ndler.}, language = {en} } @phdthesis{Antony2022, author = {Antony, Kathrin}, title = {Externe Unternehmenskommunikation unter Einbeziehung von Gr{\"u}nplanung und Bauwerksbegr{\"u}nung in der Weinbranche}, volume = {2022}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-482}, school = {Hochschule Geisenheim University}, pages = {II -- 309}, year = {2022}, abstract = {In wettbewerbsintensiven Branchen ist eine strategisch wirksame Außendarstellung ein unverzichtbarer Teil der Unternehmenskommunikation geworden. Architektur hat sich bereits als Instrument der Unternehmenskommunikation etabliert. Landschaftsarchitektur scheint hingegen unterrepr{\"a}sentiert zu sein. Die vorliegende Studie untersucht deshalb die Einbindung von Landschaftsarchitektur und Geb{\"a}udebegr{\"u}nung als Element der Unternehmenskommunikation in der Weinbranche. Erarbeitet wurden m{\"o}gliche Beitr{\"a}ge f{\"u}r eine identit{\"a}tsgerechte Außendarstellung auf der Basis einer strategischen Unternehmenskommunikation, in der die „Landschaftsarchitektur" als Teil der Corporate Identity verortet wurde. Die f{\"u}r die Arbeit erforderlichen Freir{\"a}ume am Unternehmensstandort wurden definiert. Erkenntnisse aus der Umweltpsychologie im Hinblick auf eine relevante Mensch-Umwelt-Beziehung flossen ein. Vor diesem Hintergrund wurde die Landschaftsarchitektur als ein m{\"o}gliches strategisches Kommunikationsinstrument identifiziert. Im Rahmen der Direktvermarktung wurde die Bedeutung einer entsprechenden Gestaltung der Weing{\"u}ter aufgezeigt, die ein unverzichtbarer Teil der Außendarstellung ist. Drei Hypothesen wurden aufgestellt: (1) Von Weing{\"u}tern in Deutschland, die Architektur als Instrument der externen Kommunikation einsetzen, nutzt nur ein kleiner Anteil Landschaftsarchitektur und Geb{\"a}udebegr{\"u}nung als Instrument der externen Kommunikation. (2) F{\"u}r Weing{\"u}ter haben die Landschaftsarchitektur/Geb{\"a}udebegr{\"u}nung und ihre Intensit{\"a}t Einfluss auf die von Weinkonsumenten wahrgenommene Attraktivit{\"a}t. (3) Die Ausgestaltung der Landschaftsarchitektur/Geb{\"a}udebegr{\"u}nung hat Einfluss auf Assoziationen hinsichtlich strategischer Merkmale von Weing{\"u}tern. Entwickelt wurde eine Methodik, die es erlaubte, die aktuelle Rolle von landschaftsarchitektonischer Gestaltung bei Weing{\"u}tern und deren Einbindung in die Unternehmenskommunikation zu analysieren. Auf Basis dieser Ergebnisse wurde ein Modell „Weingut mit Innenhof" und „Umfeld" entwickelt, das die Grundlage f{\"u}r eine Konsumentenbefragung bildete. 598 Probanden wurden in einem strukturierten Interview befragt und ihre Pr{\"a}ferenzen und Assoziationen in Bezug auf Begr{\"u}nungstypen und -intensit{\"a}ten analysiert. Ein Zusammenhang zwischen Begr{\"u}nung und strategischen Ausrichtungen wie Kundenfreundlichkeit, hohem Preisniveau, hoher Qualit{\"a}t, {\"o}kologischer Produktion und Handwerklichkeit wurde untersucht. Die Ergebnisse zeigen, dass eine landschaftsarchitektonische Gestaltung insbesondere in Hinblick auf die Begr{\"u}nung bei der Außendarstellung deutscher Weing{\"u}ter unterrepr{\"a}sentiert ist. Die Einbindung von Landschaftsarchitektur und Geb{\"a}udebegr{\"u}nung kann wesentlich zu einer attraktiveren Außendarstellung beitragen, insbesondere im Hinblick auf das Nachhaltigkeitsprofil. Die Begr{\"u}nungsintensit{\"a}t spielt dabei eine maßgebende Rolle.}, language = {de} } @phdthesis{Kleih2022, author = {Kleih, Anne-Katrin}, title = {Fresh fruit and vegetable branding: Investigating consumer behavior with visual and mixed methods}, volume = {2022}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-476}, school = {Hochschule Geisenheim University}, pages = {I -- 157}, year = {2022}, abstract = {This dissertation addresses two different but connected aspects of consumer research in the horticultural sector: the first pertains to the empirical level regarding consumer behavior toward branded fresh fruit and vegetables and the second to the methodological level regarding the visual method of using photos in the research process, which aids in studying the visual side of consumer behavior toward branded fresh produce. Branding is a key tool for marketing food products that benefits both producers and consumers. Moreover, brands play a crucial role in the purchase process of processed food. However, fresh fruit and vegetables are mostly sold without branding. This affects consumer behavior, as do the horticultural market structure (which is marked by strong competition), interchangeability of products, and sensitive and low prices. Many studies have investigated consumer behavior toward branded processed food. However, it is unclear whether their findings can be applied to the purchase process of fresh fruit and vegetables. Studies concerned with the effect of fresh fruit and vegetable branding on consumer behavior and that apply methods to investigate the rather implicit aspects of the effect of such branding on consumer behavior are lacking. The visual aspect of food is a central feature to which consumers react, and branding has a visual and implicit effect on consumer behavior. Therefore, visual methods are well-suited to investigating consumers' food behavior. One possible visual method involves the integration of photos into the research process. Photos have been employed in consumer research; however, their content has not usually been analyzed. The use of photos in qualitative consumer research has been mostly limited to supporting other research methods (e.g., stimuli for interviews) and, in quantitative research, to use for mere descriptive-level analysis. There is a lack of studies concerned with how to use photo analysis in consumer research and methodological reflections on how to integrate (combine) quantitative and qualitative photo analyses. To fill these gaps, this dissertation conducted two primary investigations. The first examined consumers' reactions to fresh fruit and vegetable branding with regard to their choice (process), thoughts, visual perceptions, and recall, as well as to identify and characterize relevant consumer segments by employing various methods to observe unconscious consumer behavior under research conditions that are as realistic as possible. The second aimed to identify challenges of using photos in consumer research and to develop a mixed methods framework for integrating quantitative and qualitative photo analyses. In order to achieve these aims, visual and mixed methods approaches were applied to both aspects. Eye tracking, standardized questionnaires, qualitative interviews, a choice-based conjoint experiment, and think aloud protocols were used. With regard to the empirical level of consumer behavior toward branded fresh fruit and vegetables, the results showed that consumers neither paid much visual attention nor gave much thought to fresh produce branding when making choices. Instead, consumers mainly used the visual features of the fresh produce itself as cues for decision-making. However, it was discovered that this low level of (visual) attention to branding in supermarket fruit displays may be diminished further by deficits in the presentation of branded fresh produce since manipulated and saliently displayed branding were found to improve visual capture, the decision-making process, and brand recall. Furthermore, the results revealed that some consumer groups might be of special interest to the marketing and branding efforts of fresh fruit and vegetables: 1) brand-oriented consumers especially benefited from salient branding by exhibiting shorter decision times; and 2) consumer segments that preferred branded fresh produce shared a higher level of the personality trait "food and beverage need for uniqueness". With regard to the methodological level of how the visual method of using photos was addressed, the applicability, utility, and challenges of using photos in qualitative interviews were analyzed and discussed. A number of practical challenges in conducting a photo-based qualitative interview were identified, as well as the challenge of analyzing numerous photos (quantitative) while not neglecting the detailed analysis of single photos (qualitative). This novel methodological challenge of photo analysis for mixed methods research was addressed by investigating the principles of different methods of analyzing photos from different scientific fields. In light of this investigation, a procedural mixed methods framework for analyzing photographic material was developed and illustrated with an example from consumer research. The framework developed allows the integration of different quantitative and qualitative photo analyses. It was shown that photos can be integrated by means of data transformation, which is also the starting point for integration with other types of quantitative/qualitative data (numbers, text). This dissertation provides insights into the reaction of consumers toward branded fresh fruit and vegetables and, based on the findings, into how to improve the (visual) marketing of such. Furthermore, it supports the application of quantitative and qualitative photo analysis by developing a procedural framework for extending the integration in mixed methods through the use of photographic material.}, language = {en} } @phdthesis{Strub2022, author = {Strub, Larissa}, title = {Cost Efficiency and Sustainability of Steep Slope Viticulture}, volume = {2022}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-405}, school = {Hochschule Geisenheim University}, pages = {117}, year = {2022}, abstract = {Der Anbau von Reben in Steillagen ist ein wesentlicher Bestandteil der europ{\"a}ischen Weinbaukultur. In den letzten Jahrzehnten ist jedoch ein erheblicher R{\"u}ckgang der Steillagenrebfl{\"a}chen zu verzeichnen, insbesondere in Deutschland. Der erh{\"o}hte Arbeitsbedarf in diesen Lagen, der st{\"a}rkere internationale Wettbewerb und die insgesamt gesunkene Rentabilit{\"a}t dieser Lagen f{\"u}r die Weing{\"u}ter werden als Ursachen f{\"u}r den R{\"u}ckgang genannt. Eine fundierte Kostenbetrachtung verschiedener Weinbergskonstellationen im Hinblick auf die allgemeinen Anbaubedingungen und entsprechende Mechanisierungsoptionen wurde bisher jedoch nicht durchgef{\"u}hrt. Die vorliegende Dissertation tr{\"a}gt dazu bei, die Aufgabe von Steillagen aus {\"o}konomischer Sicht am Beispiel Deutschlands zu erkl{\"a}ren. Um die Produktionskosten f{\"u}r unterschiedliche Anbaubedingungen zu vergleichen, wurden in f{\"u}nf deutschen, managementgef{\"u}hrten Weing{\"u}tern {\"u}ber einen Zeitraum von drei Jahren f{\"u}r 30 Referenzlagen Arbeitszeiterfassungen auf der Basis eines transparenten Schemas von Weinbergstypen erhoben, was zu 82 Beobachtungen und {\"u}ber 3.400 Einzeldatens{\"a}tzen f{\"u}r Arbeits- und Maschinenstunden f{\"u}hrte. Nach der Bewertung der Arbeitszeitaufzeichnungen mit entsprechenden Kostens{\"a}tzen wurde der Datensatz mittels Varianzanalyse (ANOVA) mit fixen und zuf{\"a}lligen Effekten analysiert, um den Einfluss verschiedener externer Faktoren auf die Struktur der Weinbaukosten zu ermitteln. Die Analyse ergab, dass die Kostenunterschiede zwischen den Weinbergslagen auf Unterschiede in der Mechanisierungsintensit{\"a}t und den eingesetzten Maschinentypen zur{\"u}ckzuf{\"u}hren sind. Flache Lagen erm{\"o}glichen die Mechanisierung der meisten Weinbauprozesse mit sehr effizienten Maschinen. Lagen mit begrenzter Mechanisierung erfordern spezielle Maschinen, um die Hangneigung zu {\"u}berwinden. Je st{\"a}rker die Mechanisierung eingeschr{\"a}nkt ist, desto h{\"o}her ist der Bedarf an manueller Arbeit. Die Standorte mit den schwierigsten Bedingungen verhindern die Mechanisierung einzelner oder aller Prozesse. Hinzu kommt, dass spezialisierte Maschinen f{\"u}r Steillagen in der Regel h{\"o}here Kapitalkosten verursachen. Außerdem arbeiten sie langsamer, vor allem wegen der zus{\"a}tzlichen Sicherung durch Seilwinden, die das doppelte {\"U}berfahren jeder Reihe erforderlich machen. Die Ergebnisse dieser Dissertation zeigen, dass Weinbergsfl{\"a}chen, in denen keine Vollmechanisierung mit Standardmaschinen m{\"o}glich ist, mit einem erheblichen Kostennachteil behaftet sind. Die Weinbaukosten in den am st{\"a}rksten benachteiligten, manuellen Lagen betragen mehr als das 1,6-fache der Kosten in vollmechanisierten Flachlagen. Zus{\"a}tzlich zu diesen Hektar-Nachteilen sind Weinberge in Hanglagen h{\"a}ufiger von Wassermangel betroffen, die durch den Klimawandel bereits in den letzten Jahren in h{\"o}herem Maße im Vergleich zu Flachlagen aufgetreten ist und sich wohl weiter verst{\"a}rken wird. Wassermangel verursacht D{\"u}rreprobleme, die unter anderem zu unterdurchschnittlichen Ertr{\"a}gen f{\"u}hren und damit den Kostennachteil in Steillagen aus Pro-Liter-Sicht weiter verst{\"a}rken. Diese Kostennachteile k{\"o}nnen in der Regel nicht durch Preisaufschl{\"a}ge ausgeglichen werden, so dass eine L{\"u}cke zwischen erh{\"o}hten Kosten und stabilen Preisen entsteht. Dieser Befund wirft ein d{\"u}steres Licht auf die Zukunft des Steillagenweinbaus, die durch den Einfluss des fortschreitenden Klimawandels noch verschlechtert wird. Die Verbraucher zeigen keine erh{\"o}hte Zahlungsbereitschaft f{\"u}r Steillagenweine, die einen Beitrag zur Deckung der erh{\"o}hten Kosten leisten w{\"u}rde. Die einzige Chance f{\"u}r die nachhaltige Bewirtschaftung von Steillagen liegt in der {\"o}ffentlichen F{\"o}rderung. Um diese zu rechtfertigen, muss der Gesamtwert des Steillagenweinbaus unter Ber{\"u}cksichtigung zus{\"a}tzlicher {\"O}kosystemleistungen und m{\"o}glicher gesellschaftlicher Kosten ermittelt werden.}, language = {en} } @phdthesis{Grebneva2022, author = {Grebneva, Yevgeniya}, title = {The formation, sensory contribution and management of 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in grapes and wines of Vitis vinifera L.cv. Riesling}, volume = {2022}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-387}, school = {Hochschule Geisenheim University}, pages = {220}, year = {2022}, abstract = {Wine from Vitis vinifera cv. Riesling grapes is one of the most internationally renowned white wine styles worldwide. There are several aroma compounds that are fundamental to the sensory properties of Riesling wines. Two such classes of compounds are monoterpenes and C13-norisoprenoids, both of which can be influenced in the vineyard, the winery and in the bottle. The overall objective of this study was to investigate the role of certain vineyard and winemaking practices on the development of sensorial important flavour compounds in Riesling, with particular emphasis on 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). Chapter 2 investigates the effect of a manipulated light environment during grape ripening on Australian Riesling over two consecutive vintages. The application of coloured shade cloth was used to alter not only the quantity of light but also the quality of light reaching grape leaves and berries. Changes in both grape and wine composition were observed. A reduction solely in the quantity of light resulted in a significant reduction in free and total TDN concentrations. However, sensory descriptive analysis of finalised wines demonstrated a conflicting result, as increased 'kerosene-like' aroma (a common descriptor for TDN) was not always linked to higher TDN concentrations. The starting point of TDN formation is the availability of its precursors; carotenoids and their subsequent glycosylated breakdown products. Chapter 3 comprises the analysis of major grape carotenoids present in grapes under various light conditions. While several complex mechanisms involved in photosynthesis and notably the photoprotection triggered by different light qualities during the ripening period were observed, the reduction in concentration of carotenoids was significantly higher in sun-exposed samples compared to other treatments during grape ripening. The degree of carotenoid degradation could be a useful marker for the decision regarding TDN management in wine during winemaking or storage. Furthermore, Chapter 3 provides results from the analysis of C13-norisoprenoid glycosides in wines made from grapes grown under different shade cloth in correlation to their corresponding TDN concentrations. For this experiment two approaches were considered, firstly the untargeted profiling and then targeted analysis of the glycosides in wine. Glycosides related to TDN evolution in wine were tentatively identified. While trials conducted in Australia evaluated the effect of shading on the evolution of important grape and wine components in Riesling, Chapter 4 describes the significance of increased solar exposure (leaf removal) on Riesling grape and wine compositional behaviour in combination with different row orientations (East-West, Northeast-Southwest, North-South) under German field conditions. Microclimatically, East-West orientated rows maintained the lowest interior canopy light interception, Northeast-Southwest and North-South orientations lead to the highest light exposure values, peaking in the morning and afternoon, respectively. Pronounced differences in secondary metabolites were found between the different exposure levels introduced by leaf removal. Highly exposed grapes showed significantly higher bound and free TDN concentrations, however, no direct correlation was observed between elevated free TDN levels and the perception of 'kerosene-like' aroma in the wines. Finally, Chapter 5 comprises a comparative analysis of oenological practices of grape pressing and yeast selection including enzyme (β-glycosidase) addition on the extraction of TDN and related C13-norisoprenoids in finished wines. Insignificant differences were observed between the effect of whole-bunch and crushed/destemmed fruit pressings. While the choice of yeast during alcoholic fermentation did not affect TDN formation, the addition of glycosidases to musts resulted in an approximately 15\% to 25\% increases in free TDN concentrations after the wines were submitted to accelerated ageing. However, these changes were negligible when compared to the consequence of viticultural management practices. This thesis represents a valuable contribution to the understanding of the formation, management and sensory contribution of TDN in Riesling. Furthermore, this study investigated for the first time the effect of different light regimes (shade cloth) on TDN evolution which can be used to advance the management of Riesling grape production, especially during hotter summers.}, language = {en} } @phdthesis{Wasmuht2022, author = {Wasmuht, Isabel}, title = {Systematische Untersuchung von W{\"u}rzen des „OMNIUM"-Sudhauskonzepts im Vergleich zu konventionellen L{\"a}uterbottichw{\"u}rzen und deren Auswirkungen auf den gesamten Brauprozess}, volume = {2022}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-371}, school = {Hochschule Geisenheim University}, pages = {286}, year = {2022}, abstract = {Die vorliegende Arbeit befasst sich mit der Herstellung von W{\"u}rzen und Bieren mittels eines neuartigen Sudprozesses aufgrund einer integrierten, dynamischen L{\"a}utertechnologie und dem qualitativen Vergleich zu herk{\"o}mmlichen Systemen. Das Sudhaussystem OMNIUM by Ziemann® mit dem darin implementierten neuartigen Maischefiltrationsverfahren NESSIE by Ziemann® produziert W{\"u}rzen, deren Zusammensetzung sich von herk{\"o}mmlichen W{\"u}rzen unterscheidet. Erh{\"o}hte und erniedrigte Konzentrationen bestimmter Inhaltsstoffe im Vergleich zur herk{\"o}mmlichen W{\"u}rzebeschaffenheit ver{\"a}ndern die Hefeversorgung und konsequenterweise das fertige Bier. Ziel der vorliegenden Arbeit ist es, den Einfluss auf die W{\"u}rzezusammensetzung sowie das Herausl{\"o}sen bestimmter Inhaltsstoffe durch die konventionelle und neuartige Sudhaustechnologie zu bilanzieren, zu vergleichen und die Auswirkungen auf den gesamten Brauprozess zu untersuchen. Hierzu werden ober- und unterg{\"a}rige Biere mittels eines konventionellen und neuartigen Sudwerks im 30 l-Maßstab hergestellt. Die entstehenden ungekochten und gekochten W{\"u}rzen und die hieraus produzierten Biere werden umfassend analysiert. Hierbei werden neben den Prozessparametern wie Extrakt und pH-Wert, Kohlenhydrate, Gerbstoffe, Eiweißfraktionen, Fetts{\"a}uren sowie Mineralstoffe und der photometrische Jodwert erhoben. Die anfallenden Treber werden ebenfalls untersucht. Die Schaumstabilit{\"a}t des fertigen Bieres wird untersucht und das Bier mittels einer Flavournetzverkostung bewertet. Die Ergebnisse dieser Sude bilden den Basisvergleich der Sudh{\"a}user und die Grundlage der weiterf{\"u}hrenden Vertiefung. Die weiterf{\"u}hrenden Untersuchungen befassen sich mit dem aufschließbaren Extrakt der Treber des Drehscheibenfilters, dem photometrischen Jodwert und der Enzymaktivit{\"a}t von W{\"u}rzen, einer m{\"o}glichen Reduktion der Trubfracht der neuartig hergestellten W{\"u}rzen, der chemisch-physikalischen Stabilit{\"a}t sowie der Geschmacksstabilit{\"a}t der hergestellten Biere, den Gerbstofffraktionen und deren Einfluss auf die Fermentation und der Verarbeitung verschiedener Rohstoffe und Rohstoffqualit{\"a}ten mittels des Drehscheibenfilters. Abschließend wird eine theoretische Modellierung der Maischefiltration mittels eines Drehscheibenfilters erstellt und ein Scale-Up der gewonnenen Daten auf Industriegr{\"o}ße durchgef{\"u}hrt. F{\"u}r die unterg{\"a}rige Fermentation der neuartig hergestellten W{\"u}rzen wird ein Leitfaden zur Anpassung der G{\"a}rungsparameter erstellt. Die Auswertung der Ergebnisse zeigt, dass sich durch den Drehscheibenfilter im neuartigen Sudhaus im Vergleich zum konventionellen Sudhaus eine Erh{\"o}hung des Mineralstoff- und des Fetts{\"a}urespektrums und eine Verringerung des Gerbstoffzusammensetzung ergeben. Die stickstoffhaltigen Verbindungen sowie das Zuckerspektrum bleiben unver{\"a}ndert. Die neuartige W{\"u}rzebeschaffenheit erm{\"o}glicht eine um zwei Tage z{\"u}gigere und intensivere Fermentation. Durch die gesteigerte Hefevermehrung wird mehr Maltose und Maltotriose sowie Zink und Kalium aufgenommen. Dies bewirkt einen h{\"o}heren Endverg{\"a}rungsgrad der Biere. Die gute Versorgung der Hefe f{\"u}hrt zu einem tendenziell niedrigeren G{\"a}rungsnebenproduktespektrum, was durch ein angepasstes G{\"a}rverfahren korrigiert werden kann. Die Deckung der Verkostungsergebnisse zeigt, dass die Herstellung geschmacklich gleicher Biere mit den unterschiedlichen Sudh{\"a}usern m{\"o}glich ist. Durch das signifikant niedrigere Gerbstoffspektrum im Bier wird deutlich, dass eine gerbstoffseitige Stabilisierung im neuartig hergestellten Bier zu {\"u}berdenken ist. Ein Einfluss der Gerbstoffe auf den Hefemetabolismus konnte ausgeschlossen werden. Insgesamt ist die chemisch-physikalische Stabilit{\"a}t und Geschmacksstabilit{\"a}t der neuartig hergestellten Biere als sehr gut zu bewerten. Die Schaumstabilit{\"a}t unterscheidet sich nicht zu konventionell hergestellten Bieren. Die signifikant h{\"o}here W{\"u}rzetr{\"u}bung ist im Bier nach der Sedimentation mit der Hefe w{\"a}hrend der G{\"a}rung nicht wieder zu finden. Zus{\"a}tzlich kann großtechnisch die Trubfracht ohne Beeintr{\"a}chtigung der Inhaltsstoffe mittels einer Zentrifuge verringert werden. Es zeigt sich, dass der photometrische Jodwert unabh{\"a}ngig des Einsatzes eines heißen Malzauszuges {\"u}ber die Fermentation hinweg absinkt. Ein direkter Zusammenhang mit der enzymatischen Aktivit{\"a}t des heißen Malzauszuges konnte nicht nachgewiesen werden. Prinzipiell erm{\"o}glicht die dynamische Siebfiltration mit der angeschlossenen diskontinuierlichen Extraktion die Verarbeitung verschiedener Rohstoffe und verschiedener Rohstoffqualit{\"a}ten. Die Ergebnisse sind auf den industriellen Maßstab {\"u}bertragbar.}, language = {de} } @phdthesis{Bernardi2021, author = {Bernardi, Beatrice}, title = {Characterization of hybrid genes and copy number variations in lager yeast strains}, volume = {2021}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-366}, school = {Hochschule Geisenheim University}, pages = {135}, year = {2021}, abstract = {ZUSAMMENFASSUNG Lagerhefen sind hybride Organismen, welche aus einer Zellfusion zweier Spezies der Gattung Saccharomyces, S. cerevisiae und S. eubayanus, entstanden sind. Vorg{\"a}nge, welche nach der Hybridisierung stattfinden, wie zum Beispiel die Ver{\"a}nderung der Kopienzahl (CNV), der Chromosomenverlust, wechselseitige Translokationen oder interchromosomale Neuordnungen k{\"o}nnen die Genomgr{\"o}ße, die Ploidie oder die Sporulationseffizienz beeinflussen. Bei polyploiden Hybriden erschwert das Vorhandensein mehrerer Allele eines Gens funktionelle Studien, die auf einer Gen-Manipulation beruhen, z. B. Gen- Deletionen. Die meisten an Hefen angewendeten gentechnischen Methoden basieren auf die homologe Rekombinationsmaschinerie (HR) der Hefe, die bei S. cerevisiae hervorragend funktioniert, bei Lagerhefen jedoch eine geringe Effizienz aufweist. In dieser Arbeit entwickelte ich eine Strategie zur Verbesserung der HR-Effizienz von Lagerhefe, die ein kurzflankiges (sf) PCR-basiertes Gen-Targeting erm{\"o}glicht. Die HR-Effizienz wurde erfolgreich durch eine {\"U}berexpression von RAD51 verbessert, das einen Schl{\"u}sselregulator des HR-Signalwegs codiert, der die Suche nach komplement{\"a}ren DNA-Str{\"a}ngen w{\"a}hrend der Rekombination {\"u}bernimmt. Die erfolgreiche Verbesserung des sf-PCR-basierten Gen-Targetings in Lagerhefe wurde durch Targeting der von S. cerevisiae abgeleiteten Loci von ADE2 und HSP104 in der allotetraploiden Lagerhefe Weihenstephan 34/70 gezeigt. Diese Technik kann nun zur Vereinfachung der Gentechnik in Lagerhefe verwendet werden, z. B. durch Ver{\"a}nderung der Expression spezifischer Gene, die an der W{\"u}rzefermentation und der Geschmacksbildung beteiligt sind. Andere Mechanismen der Genomentwicklung sind die Aufnahme von DNA durch horizontalen Gentransfer oder Introgression. Diese wurden in einem Apfelwein-Hefestamm genauer untersucht. Die Genomsequenzierung zeigte, dass es sich um ein bestimmtes Saccharomyces uvarum Isolat handelt. Interessanterweise haben wir bei diesem Stamm die {\"U}bernahme von ~100 kb der DNA von S. eubayanus identifiziert, die 54 Gen-ORFs auf Chromosom XIV enth{\"a}lt. Eine auf DNA-Polymorphismus basierende Analyse legt nahe, dass einLagerhefestamm wahrscheinlich eher der elterliche Spender dieser DNA ist als ein S. eubayanus-Stamm. Eine zus{\"a}tzliche DNA-Insertion mit starker {\"A}hnlichkeit zu Torulaspora microellipsoides wurde auf Chromosom XII gefunden. Die Introgression dieser speziellen DNA-Region wurde zuvor bei mehreren Weinhefest{\"a}mmen beobachtet. Diese enth{\"a}lt 19 weineigene Gene wie FOT1/FOT2, die f{\"u}r den Pilz-Oligopeptid-Transporter Fot kodieren, der Vorteile bei der Stickstoffverwertung bietet. Auffallend ist, dass das S. uvarum- Apfelweinisolat die S. cerevisiae EC1118, welche als Zugpferd der Weinindustrie in Standard- und Kaltg{\"a}rungen gilt, {\"u}bertrifft und verdr{\"a}ngen k{\"o}nnte. Bier- und Weinhefen zeichnen sich durch ihre Flokkulations-Eigenschaften am Ende der Fermentation aus. Die Flokkulation ist die F{\"a}higkeit, Zellflocken zu bilden, ein entscheidendes Merkmal f{\"u}r Industriehefe, das eine einfache Trennung von Zellen vom jungen Getr{\"a}nk erm{\"o}glicht. Um NCY in einen bestehenden Brauprozess zu implementieren, m{\"u}ssen diese Hefen an die aktuelle Brautechnik anpassbar sein. Daher wurden in dieser Arbeit die Flokkulations-Eigenschaften einer NCY Saccharomycopsis fermentans Hefe charakterisiert. Ich konnte zeigen, dass die Flokkulation von S. fermentans wie bei S. cerevisiae Ca2+ abh{\"a}ngig ist. Durch eine PacBio-Genomsequenzierung wurden, basierend auf der {\"A}hnlichkeit mit den FLO1/5/9-Genen von S. cerevisiae und der ALS-Genfamilie von Candida albicans, 34 Flokkulationsgene in S. fermentans identifiziert und als FAS (f{\"u}r FLO/ALS-{\"a}hnliche Sequenzen) bezeichnet. Zudem wurde festgestellt, dass sich FAS-Gene in subtelomeren und telomeren Regionen befinden, ebenso wie die Flokkulationsgene von S. cerevisiae. "Telologe" - orthologe oder paraloge Gene, die sich an Telomeren befinden - war ein neuartiger Begriff, der eingef{\"u}hrt wurde, um Gene zu identifizieren, die einen evolution{\"a}r konservierten genomischen Ort teilen.}, language = {en} } @phdthesis{Boehm2020, author = {B{\"o}hm, Matthias}, title = {Wildunf{\"a}lle in Hessen - Ursachen, Schutzmaßnahmen und neue Konzepte -}, volume = {2021}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-330}, school = {Hochschule Geisenheim University}, pages = {470}, year = {2020}, abstract = {Wildunf{\"a}lle stellen deutschlandweit und insbesondere in waldreichen Bundesl{\"a}ndern wie Hessen zeitweise bis zu einem Drittel der Gesamtunf{\"a}lle dar. Im Mittelpunkt der vorliegenden Dissertation steht die folgende Forschungsfrage: Welche Parameter bestimmen die raum-zeitliche Verteilung von Wildunf{\"a}llen und wie k{\"o}nnen Entscheidungstr{\"a}ger aus Politik, Wirtschaft und Verb{\"a}nden aktuell und angesichts der technologischen Entwicklung eine bestm{\"o}gliche Senkung der Unfallzahlen herbeif{\"u}hren? In einem zweiteiligen Ansatz wird zun{\"a}chst eine Analyse der seitens der hessischen Polizei aufgenommenen Unfalldaten der Jahre 2006 bis 2016 durchgef{\"u}hrt, um Hypothesen zu den Einflussfaktoren zu beantworten. Aufbauend auf einem Forschungsprojekt der Bundesanstalt f{\"u}r Straßenwesen (BASt) werden die zehn gravierendsten hessischen Schwerpunktstrecken ermittelt und f{\"u}r diese eine Umfeldanalyse mit beh{\"o}rdlichen GIS-Daten durchgef{\"u}hrt. Die Ergebnisse werden mit den Werten von zufallsbasiert gew{\"a}hlten, unfallunauff{\"a}lligen Abschnitten verglichen. Weiterhin werden die o. g. {\"u}ber 170.000 Unfallreporte ausgewertet. Die Resultate der Analysen werden anhand der Fachliteratur mit dem aktuellen Stand der Forschung verglichen. Im zweiten Schritt wird die in die Unfallpr{\"a}ventionsarbeit involvierte Akteurslandschaft mittels Szenariotechniken zur Strategieentwicklung untersucht. Anhand der gewonnenen Erkenntnisse {\"u}ber die Dynamiken und Potenziale wird ein Handlungskonzept erarbeitet und mit Vertretern der Stakeholder diskutiert. Abschließend werden auf der Grundlage des in den beiden Arbeitsschritten gewonnenen Wissens Entscheidungsgrundlagen und Handlungsempfehlungen f{\"u}r die beteiligten Akteure erarbeitet. Den deutlichsten Einfluss auf das Unfallrisiko hat der Faktor D{\"a}mmerung, w{\"a}hrend der sich je nach Tierart bis zu zwanzigmal so viele Kollisionen als {\"u}ber vergleichbare Zeitspannen bei Tageslicht ereignen. In der Analyse der jahreszeitlichen Verteilung zeigen sich zudem deutliche Schwerpunkte w{\"a}hrend der Paarungszeiten und Revierk{\"a}mpfe. Hinsichtlich der Landschaftsmatrix f{\"u}hren erh{\"o}hte Anteile von Landwirtschafts- und Waldfl{\"a}chen nicht zwingend zu der Entstehung von Unfallschwerpunktstrecken, vielmehr muss die individuelle Komposition der {\"O}rtlichkeit untersucht werden. Die N{\"a}he von großen Fließgew{\"a}ssern und Seen hingegen bewirkt einen steigernden Einfluss auf die Unfallzahlen. Dichteunterschiede der Wildunfallh{\"a}ufigkeit je nach Tierart zeigen sich meist nur im gr{\"o}ßeren Maßstab; im Westen Hessens dominieren Reh-, im S{\"u}den Schwarzwildunf{\"a}lle. Die Unf{\"a}lle geschehen zu 70 \% m{\"a}nnlichen Fahrern, insbesondere in den Altersgruppen 20-24 sowie 45-50 Jahren. Insbesondere der Herbst bietet sich f{\"u}r Warnaktionen an, beispielsweise durch tempor{\"a}r aktivierte LED-Schilder. Bez{\"u}glich der effektivsten klassischen Gegenmaßnahme, dem Wildschutzzaun, besteht die Notwendigkeit zu einer besseren Datenhaltung der Beh{\"o}rden sowie einer Novellierung der Richtlinie zu den Einsatzkriterien f{\"u}r und der Konstruktion der Zaunsysteme. Die Prozesslandschaft zeichnet sich dadurch aus, dass die meisten Akteure nur wenig Initiative zeigen und gleichzeitig lediglich geringem Handlungsdruck unterliegen. Es bestehen keine Interessenskonflikte, sondern eher zeigt sich Synergiepotenzial. Zentral ist zuallererst, die haupts{\"a}chlich organisatorischen Aufgabenstellungen wie ein {\"u}bergeordnetes Großprojekt zu starten und eine zentrale Open-Data Meldeplattform einzurichten. Hier sind die Politik und Einrichtungen wie die Bundesanstalt f{\"u}r Straßenwesen gefordert. Nur mit ihrer Initiative k{\"o}nnen klassische Maßnahmen optimiert, innovative L{\"o}sungen in Kooperation mit der Automobilindustrie und IT-Dienstleistern eingef{\"u}hrt und das volle Potenzial der sich aktuell weiterentwickelnden Technologie zur Unfallpr{\"a}vention ausgesch{\"o}pft werden.}, language = {de} } @phdthesis{Hendgen2021, author = {Hendgen, Maximilian}, title = {Beeinflussung der Seneszenz bei Weinreben als Anpassungsstrategie an den Klimawandel}, volume = {2021}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, isbn = {13 978-3-934742-85-7}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-329}, school = {Hochschule Geisenheim University}, pages = {211}, year = {2021}, abstract = {Blattseneszenz stellt bei Pflanzen einen genetisch geregelten, komplexen Alterungsprozess dar. Sie wird durch die Kombination von Umwelt- und Altersfaktoren ausgel{\"o}st und dient dem Recycling von N{\"a}hrstoffen. Charakteristisch f{\"u}r die Blattseneszenz sind eine erh{\"o}hte Expression von Seneszenz-assoziierten Genen (SAGs), der Abbau von Chlorophyll und die R{\"u}ckverlagerung von N{\"a}hrstoffen, insbesondere von Stickstoff (N). Bei der Weinrebe Vitis vinifera dient N nicht nur dem pflanzlichen Wachstum, sondern auch der Hefeern{\"a}hrung w{\"a}hrend der alkoholischen G{\"a}rung des Mostes. Der Gehalt an hefeverf{\"u}gbarem N (YAN) in der Beere h{\"a}ngt sowohl von der N-Verf{\"u}gbarkeit des Standorts, als auch von der N-Einlagerung w{\"a}hrend der Reife ab. Durch den Klimawandel erfolgen Traubenreife und Blattseneszenz zunehmend zeitlich entkoppelt, wodurch im Most der in n{\"o}rdlichen Anbaugebieten sp{\"a}treifenden Rebsorte Vitis vinifera cv. Riesling der f{\"u}r eine gute Verg{\"a}rbarkeit empfohlene Zielwert von 150 mg/L YAN nicht erreicht wird und das Risiko von G{\"a}rproblemen steigt. Daher wurde in dieser Arbeit auf zwei Standorten mit unterschiedlicher N-Verf{\"u}gbarkeit und in zwei Jahren untersucht, ob durch eine Behandlung mit Ethephon oder UV-C vor der Lese Blattsenszenz induziert, und durch Umverlagerung des remobilisierten N in die Beere eine ausreichende Konzentration an YAN im Most erzielt werden kann. Die Ethephon-Behandlung induzierte Blattseneszenz zuverl{\"a}ssig und schnell, ihre N-Remobilisierung wie auch ihre Genexpression glichen der von nat{\"u}rlicher Seneszenz. Die UV-C-Behandlung erzeugte ebenfalls Seneszenz-Symptome, sie erreichte jedoch nicht die Effektivit{\"a}t der Ethephon-induzierten und der nat{\"u}rlichen Seneszenz. Auf dem Standort mit geringer N-Verf{\"u}gbarkeit konnte durch die Ethephon-Behandlung die YAN-Konzentration im Most gesteigert werden, durch die UV-C-Behandlung hingegen nicht. Auf dem Standort mit guter N-Verf{\"u}gbarkeit hatte keines der beiden Verfahren einen Effekt auf die Most-N-Versorgung. Die erreichten YAN-Steigerungen verbesserten die Verg{\"a}rbarkeit, obwohl der Zielwert von 150 mg/L in keinem Fall erreicht wurde. Die zur Sicherstellung einer guten G{\"a}rleistung empfohlene YAN-Konzentration im Most ist daher kritisch zu {\"u}berpr{\"u}fen.}, language = {de} } @phdthesis{Pabst2020, author = {Pabst, Evelyn}, title = {Effects of potential EU regulation on mandatory nutrition and ingredient labelling for wine}, volume = {2021}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-253}, school = {Hochschule Geisenheim University}, pages = {68}, year = {2020}, abstract = {With the exception of ingredients that may have an allergenic effect, alcoholic beverages with above 1.2\% alcohol by volume are currently exempt from mandatory nutrition and ingredient labelling. In 2017, however, the European Commission decided that, in order to protect consumer interests, further exemption from this special regulation could not be justified. Mandatory nutrition and ingredient labelling for wine will affect not only all European producers but also every international producer who exports wine to an EU member state. Many studies have investigated how consumers behave in relation to nutrition labelling and ingredient listings for food in general, but only a few have considered alcoholic beverages and wine specifically. Existing studies of wine are limited to quantitative approaches that focus on consumers' stated interests regarding ingredient and nutrition information, utilising the direct elicitation of stated preferences. These methods are prone to greatly overestimate the effect. There is a lack of more indirect observational studies in more realistic settings that analyse consumers' emotional and verbal reactions when confronted with ingredient and nutrition information on a bottle of wine as well as the implications that this information will have on their choice behaviour. Finally, there is a lack of empirical research on the consequences that mandatory nutrition and ingredient labelling will have for producers. In order to fill these gaps, the main objectives of this dissertation are the following: First, to analyse consumers' reactions to nutrition and ingredient labelling covering their emotional reactions and the effect on wine choice and demand as well as the influences of additional information, time and country. Second, to examine the consequences that producers are facing with regard to nutrition and ingredient labelling for wine by analysing producers' expectations of consumer reactions as well as the effects on production processes and competitive advantages. A multi-stage multi-method research design, which combined qualitative focus groups and a discrete choice experiment, was utilised to analyse consumers' reactions to nutrition and ingredient labelling for wine across several countries. In order to analyse the consequences that the potential new EU labelling law will have for wine producers, an exploratory online survey to ask producers directly was utilised. The results suggest that the wine industry will face considerable challenges once nutrition and ingredient labelling is mandatory. Consumers' emotional reactions, especially to the ingredients in wine, are rather negative, and they are becoming less likely to view wine as a very natural product. Average wine-involved consumers were shown to place a considerable amount of importance on nutrition information in a retail setting and prefer to receive complete information. Without additional guidance, consumers only place low importance on ingredient information, but this changes when they are negatively confronted with the topic. Negative information has the potential to affect how consumers choose wine by increasing the attention they pay to ingredients, at the cost of the attention directed at sensory descriptions, and by changing consumers' preferences to shorter ingredient lists. Some consumers in traditional wine markets are even likely to refrain from buying wine in the case of negative media coverage. While consumers will be strongly affected by nutrition and ingredient labelling in the short term, they are likely to adapt to this information in the mid to long term, which will reduce the effect of negative media coverage. In addition to the effects on consumer behaviour, mandatory nutrition and ingredient labelling will likely also change production processes and competitive advantages within the wine industry. In order to actively avoid declarable substances, some producers will change their oenological practices, which might lead to a deterioration in wine quality and higher wine prices. Providing correct nutrition and ingredient information for each batch will make the labelling process more difficult and more expensive. Although consumers highly value sensory information, this information is likely to be reduced or eliminated when nutrition and ingredient labelling is introduced as the competition for space on back labels will increase. The introduction of mandatory nutrition and ingredient labelling is also likely to affect competitive advantages between wine producers. Producers that are able to and willing to adapt will have the chance to gain competitive advantages. Overall, producers are advised to adapt their communication strategies to actively promote the reasons for the use of ingredients in wine production in order to reduce the effects of negative media coverage. The industry should also prepare in advance for changes in production processes and potential changes in consumer preferences because mandatory nutrition and ingredient labelling will likely be introduced within the next few years.}, language = {en} } @phdthesis{Brandt2021, author = {Brandt, Melanie}, title = {The influence of abiotic factors on the composition of berries, juice and wine in Vitis vinifera L. cv. Riesling}, volume = {2021}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-260}, school = {Hochschule Geisenheim University}, pages = {269}, year = {2021}, abstract = {Grapevine physiology and berry composition are highly influenced by abiotic factors, and this, in turn, affects wine composition and aroma. Primary metabolites, like sugars and acids, and also secondary metabolites, like phenols and terpenes, are sensitive to climatic conditions. However, the developmental stage of the berries and the environmental conditions within the bunch zone play a crucial role determining the different pathways of the metabolites and hence its concentration. This study aimed to investigate the influence of abiotic factors on the composition of berries, juice and wine of Vitis vinifera L. cv. Riesling. Field experiments were carried out in an experimental site of Hochschule Geisenheim University [Eibinger Magdalenenkreuz, Germany (49° 59'20'' N; 7° 55'56'' E)] using Riesling [clone 198-25Gm; grafted on rootstock SO4 Gm47 (Vitis berlandieri x V. riparia)]. In a non-irrigated vineyard, planted in 2007, the vines were trained to a vertical shoot position canopy system. The impact of global warming and rising temperature was one of the main questions of this thesis, and was simulated by an open heating system (OHS) in the vineyard. The tent-like construction passively heated the bunch zone. The effect of higher sun exposure on berries was trialed by the defoliation of the bunch zone at different stages of berry development. The removal of leaves around bunches is commonly used in coolclimate viticulture to improve the health status of berries and influence the aroma profile. Due to the increasing numbers of sunshine hours as well as the rising temperatures caused by climate change, the question then arises if in future defoliation practices will be the method of choice. Additionally, and in contrast, some bunches were placed in light-excluding boxes to simulate full shading. On days with high radiation, the open heating system clearly elevated temperatures compared to the control and the defoliation treatments. In the bunch zone above the open heating system, the air temperature was 4 °C higher compared to the other treatments. Inside the open heating system, the temperature was up to 13 °C higher. On days with low radiation, there was a minimal temperature difference between the treatments. The porosity of the bunch zone was quantified by a novel approach using lightsensitive films which provide a simple and accurate method for characterizing light conditions and quantifying cumulative radiation within the canopy. Different lightsensitive film qualities allow the measurement over a short period (3-7 days) or a more extended period (1-3 weeks). One of the significant advantages of this method will be that simultaneous measurement of several points will be possible. The health status of the berries was improved by defoliation and the infection (incidence and severity) of Botrytis cinerea reduced compared to the control providing a faster drying of bunches after morning dew or rainfall. Similarly, the OHS promoted airflow inside the bunch zone, causing same effects. Higher temperatures significantly reduced the berry weight, with the effect more pronounced if higher temperatures occurred before v{\´e}raison. Berries grown under higher temperatures showed lower total soluble solids and the glucose to fructose ratio was impacted by lower glucose concentrations. A change in the glucose to fructose ratio will be of relevance for the fermentation since most yeasts prefer glucose over fructose. Defoliation treatment had no impact on the total soluble solids. In contrast, intense radiation or shading did not affect the berry size while extreme shading of the bunches reduced total soluble solids. Tartaric acid was not significantly influenced by higher temperatures or radiation, but malic acid concentrations strongly declined under warmer conditions. This decreased the total acidity in juice and wine, which is of particular importance for the wine profile of Riesling. The defoliation practices showed only little effect on the acid concentrations whilst the extreme shading treatments strongly increased the acidity. The analysis of phenols in berry skin was performed by high-performance liquid chromatography (HPLC) coupled to a photodiode array (PDA) detector and quantified with an external calibration. Flavonols, in particular, were influenced by higher sun exposure, with significantly higher flavonol concentrations found in the defoliation treatments. The time point when defoliation was applied had only small effects on the final total flavonol concentration. On the other hand, when a sunny period occurred after v{\´e}raison flavanols revealed high concentrations after defoliation. Sunny periods before v{\´e}raison or a ripening period with low sunshine hours did not increase the flavanol concentration compared to the control. No impact of the defoliation on the group of hydroxycinnamic acids, non-flavanoids, was The sensory assessment with small scale-vinifications was diverse. Only in the younger vintage, the panellists were able to detect differences in wines, which were mainly based on total acidity. The influence of the treatments to the grapes, which were observed for primary and secondary metabolites in berries and juice, were found in wine as well. The only expectation was TDN. In wines, higher TDN concentrations were always detected for the late defoliation. The early defoliation contained higher TDN concentrations if a sunny period occurred before v{\´e}raison. Also, elevated temperatures caused higher TDN levels in wine. The prediction of the precise temperature and light conditions influencing TDN will require detailed investigations. A new approach was developed to analyse and quantify free and glycosidically bound monoterpenes and C13-norisoprenoids in berries, juice and wine. The sample volume was reduced by 90\% and free analytes were directly analysed from the matrix with only little sample preparation. This simplified the analysis, saved time and made the use of organic solvents and solid-phase extraction cartridges redundant. The method was validated and compared to other methods in literature. In juice and wine 15 monoterpenes and four C13-norisoprenoids could be analysed simultaneously and the typically concentration ranges of the samples were covered.}, language = {en} } @phdthesis{Laier2020, author = {Laier, Marcus}, title = {Analytical Characterisation and Properties of Innovative and Commercial Oenological Agents Based on Yeasts Marcus Laier}, volume = {2020}, edition = {1. Auflage}, publisher = {Gesellschaft zur F{\"o}rderung der Hochschule Geisenheim}, address = {Geisenheim}, isbn = {13 978-3-934742-81-9}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-292}, school = {Hochschule Geisenheim University}, pages = {194}, year = {2020}, abstract = {Produkte auf Basis von Hefen sind ein neuer Trend in der {\"o}nologischen Anwendung. Hefeprodukte (YDPs) werden in jeder Phase der Weinherstellung eingesetzt, vom Weinberg bis zum Wein. Die meisten Produkte sollen als N{\"a}hrstoffversorgung entweder die alkoholische oder die malolaktische G{\"a}rung unterst{\"u}tzen. YDPs k{\"o}nnen aber auch als Aromaverst{\"a}rker oder Sch{\"o}nungsmittel dienen. Die Anzahl der Produkte und Anwendungen nimmt st{\"a}ndig zu und somit wird die Nachfrage nach einem tieferen Einblick in dieses Thema immer wichtiger. Die vorliegende Dissertation dient als Basis f{\"u}r weitere Studien und Charakterisierungen der Hefederivate (YDPs). Des Weiteren zeigt sie, dass die Themen, die weiter verfolgt und an denen in Zukunft geforscht werden kann, vielf{\"a}ltig sind. Bereits existierende Methoden k{\"o}nnen angewandt werden, wobei fallweise Adaptionen notwendig sind. Standardverfahren (SOPs) f{\"u}r weitere reproduzierbare Analysen k{\"o}nnen bereitgestellt werden. F{\"u}r die meisten Parameter sind beachtliche Schwankungen zwischen den Proben zu verzeichnen. Nur Ammonium und die Tr{\"u}bung (NTU) bilden Ausnahmen. Der Parameter "wasserl{\"o}slicher Anteil" zeigt den gr{\"o}ßten Einfluss. Hochl{\"o}sliche Proben zeigen meist einen h{\"o}heren Gehalt an den gemessenen Parametern im Vergleich zu Proben mit geringerer L{\"o}slichkeit (und h{\"o}herem Anteil unl{\"o}slicher Masse). Dies f{\"u}hrt zur Schlussfolgerung, dass die YDPs aus zwei Gruppen - abh{\"a}ngig von der L{\"o}slichkeit - bestehen. Diese zwei Gruppen m{\"u}ssen bei der (multi-variaten) Datenauswertung und -interpretation, sowie bei der Kalibration spektroskopischer Methoden getrennt gehalten werden. Die multi-variate Datenexploration erweist sich als hoch effektiv und aufschlussreich. Ausreißer k{\"o}nnen detektiert und erkl{\"a}rt werden. Sowohl die FTIR-Messungen der Eluate und Suspensionen, als auch die UV-VIS/NIR-Messungen ergeben {\"a}hnliche Resultate. Spektroskopische Methoden sind starke Werkzeuge zur Analyse und Charakterisierung von Hefederivaten. Die Datenvorbereitung ist entscheidend und unabdingbar, aber L{\"o}sungen k{\"o}nnen aufgezeigt werden. Die Kalibrationen f{\"u}r die verschiedenen spektroskopischen Methoden sind vielversprechend. Dies beweist, dass es lohnt, auf diesem Feld weiterzuarbeiten. Einzig die ATR-FTIR zeigte zu viele Mankos. Die UV-VIS/NIR-Kalibrationen k{\"o}nnten verbessert werden, indem eine pr{\"a}zisere und f{\"u}r die Proben besser geeignetere Apparatur verwendet wird. Eine Gruppierung nach der L{\"o}slichkeit ist die einzige Gruppierung, die mit dem Datensatz dieser Studie vorgenommen werden kann. Weder die Gruppierung nach der Hauptanwendung, noch nach dem Hersteller zeigt ein Muster. Eine Trennung von oenologischen Produkten und Produkten aus der Lebensmittelindustrie zeigt sich nicht. Die Produkte der Lebensmittelindustrie sind hochl{\"o}slich und k{\"o}nnen von den weniger l{\"o}slichen oenologischen Produkten unterschieden werden. Allerdings k{\"o}nnen die l{\"o}slichen oenologischen Produkte (Hefeextrakte, Mannoproteine) nicht von den Produkten f{\"u}r die Lebensmittelindustrie unterschieden werden.}, language = {en} } @phdthesis{Zeng2021, author = {Zeng, Lishi}, title = {Drivers and inhibitors of consumer adoption to a new product category in emerging market: the case of wine in China}, volume = {2021}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim, Germany}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-203}, school = {Hochschule Geisenheim University}, pages = {151}, year = {2021}, abstract = {Past adoption research has focused on new ideas, services and consumer durable goods where the first purchase is sufficient to be regarded as the act of adoption. Adoption studies rarely expand its application on new consumer packaged goods (CPGs) where subsequent repeat purchases are in high demand. Every year, the CPG industry spends a large amount of budget on developing and launching new products into the market in order to generate competitiveness, hence yielding financial growth. Despite the fact that new products have been carefully designed and tested before launch, the majority of them still fail. Consumers may talk the talk in pre-market tests but walk the walk after product launch. Such a gap between stating an intention for the future and taking action in the proximal may come from a lack of understanding the dynamic nature of the adoption process. Consequently, this thesis investigates the process and antecedents of adopting new CPGs, which is also known as fast moving consumer goods (FMCGs). This thesis aims to unveil how the influence of adoption antecedents change along the process. Three research questions are raised: 1) What is the adoption process of new CPGs? 2) What are the key factors of adopting a specific product category in an emerging market? 3) How do the effect sizes of these adoption factors change along the process? The wine category in China is selected to be the research context. The exploratory sequential mixed-method approach is designed in two phases. In Study 1, twenty-six face-to-face, in depth interviews with both wine adopters and non-adopters were conducted in two Chinese cities to outline the adoption process and refine the key adoption antecedents. Then the key adoption antecedents were further discussed and subjected to a hypothetical model. In Study 2, an online survey was launched to collect data from 1,567 alcohol consumers nationwide. Structural equation modelling was applied in testing the effect sizes of the adoption antecedents and corresponding process dynamic effects. The results indicate three major discoveries. 1) The adoption of new CPGs is a long process concerning repeat purchases or consumptions after the first trial. Unlike Rogers' process model (Rogers 2003), there are not many cognitive considerations before adoption behaviour occurs. The subsequent repeat purchases after the first trial are more decisive on how far a consumer can reach along the adoption journey. After the first trial, two milestone intermediate stages were identified: increasing exposure and reinforcement. Consumers start to build up the association between products and consumption occasions at the increasing exposure stage. Later into the reinforcement stage, these associations expand to more frequent consumption occasions. This empirical finding highlights the importance of understanding post-trial repeat purchases for the CPG industry and research, not just the first purchase. 2) Adoption intention is different to adoption behaviour. Different adoption outcomes have been used interchangeably in adoption research and in pre- market tests, especially adoption intention and behaviour. This study finds that adoption intention associates weakly with adoption behaviour. These two different adoption outcomes are influenced by different antecedents. Personal traits are more influential on adoption intention; while consumption behaviour and relative advantages of the new product drive adoption behaviour. This discovery suggests that adoption variables from different time points of the process should not be used interchangeably or utilise one to predict the other one. Furthermore, adoption variables should be selected carefully according to the antecedents of interest. 3) The influence of past consumption behaviour on adoption behaviour is dynamic along the adoption process. This discovery adds one more empirical evidence that adoption antecedents exhibit different influence on adoption at different behavioural stages. It sheds light on the process dynamic effect of adoption antecedents and responses to the call of process-oriented studies by adoption researchers.}, language = {en} } @phdthesis{Tafel2021, author = {Tafel, Maximilian Carl}, title = {Investigating the Characteristics and the Economic Impact of Tourism in German Wine Regions}, volume = {2021}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-188}, school = {Hochschule Geisenheim University}, pages = {124}, year = {2021}, abstract = {Wine tourism is a growing niche market around the world. Germany seems to offer an ideal platform for this promising market. However, there is very limited knowledge about the economic significance of wine tourism in Germany and about understanding visitors' needs and expectations. By proposing a framework for three different studies across all 13 German wine regions, including both the travelers' and the wineries' perspective, this thesis aims to alter the understanding of wine tourism in Germany. The three main research questions derived from a survey of the literature (see Chapter 1) are: 1. What differentiates wine tourists in Germany from other tourist segments? 2. How large is the economic impact of wine tourism in Germany? 3. How relevant is wine tourism in Germany from a winery operators' perspective? In order to separate wine tourists from other tourist segments, a quantitative study with 4,478 visitors to wine regions was carried out. By interviewing visitors at "wine-neutral" locations such as city centers or cultural sites, this approach differed from previous research. After segmentation, travelers were divided into wine tourists and other tourist segments. Then, a modified multiplier model was developed that allows measuring the economic impact of wine tourism. Finally, to include the wineries' perspective, 199 qualitative in-depth interviews and 703 quantitative online questionnaires were collected and analyzed. It is the aim of the winery surveys to reveal the relevance and main challenges of wine tourism in Germany. Results show that 7.2 million wine tourists, of whom 89\% are Germans, visit the country's wine regions each year. For them, tasting wine, enjoying nature and combining food and wine experiences are the main motivating factors for visiting a wine region. Wine tourism has a disproportionately large economic impact of EUR 5.0 billion annually, contributing to the income of 71,846 people. From an average winery operator's perspective, wine tourism accounts for 24\% of company sales. Despite an increasing demand in wine-touristic activities, the number of wineries, as well as restaurants, is declining which reduces the attractiveness for culinary-focused wine tourists. To successfully develop wine tourism in Germany, there is a clear need for collaboration among stakeholders. Furthermore, the preservation of cultural landscapes plays an important role in attracting visitors. This thesis advances the understanding of wine tourism in Germany from a visitor's as well as a winery's point of view. The approaches developed for segmenting wine tourists and for assessing the economic impact of wine tourism can be applied in any wine region of the world. They can also be transferred to other forms of special-interest tourism (e.g. alpine tourism and culinary tourism). The findings and discussions can be used for teaching students and training stakeholders at the regional, entrepreneurial and personal level. Wine tourism could help to balance inequalities between rural and urban areas in terms of income and employment levels. This, combined with the preservation of natural resources and cultural landscapes, could lead to sustainable regional development in the German wine regions.}, language = {en} } @phdthesis{Uzman2020, author = {Uzman, Deniz}, title = {Effects of landscape structure and farming type on biodiversity and ecosystem functions in vineyard ecosystems}, volume = {2020}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-148}, school = {Hochschule Geisenheim University}, pages = {182}, year = {2020}, abstract = {Almost 40\% of the world's terrestrial surface is covered by agriculture. Thus, agricultural land is of particular importance for the conservation of biodiversity. At the same time, the intensification of management practices and the concomitant homogenization of landscapes are main drivers for a severe loss of biodiversity. The protection of arthropods in agricultural landscapes has gained increased attention facing the current biodiversity crisis. In agricultural landscapes, grapevine is a particularly intensively managed crop, which is characterised by frequent application of fungicides. On the other hand, vineyards and especially the inter-rows between vines with their permanent character can serve as habitats for many organisms. Additional nesting and feeding resources for beneficial arthropods can be provided. Measures to enhance biodiversity in viticulture mainly encompass organic management and the management of inter-row vegetation cove, for example by tillage regime or the use of seed mixtures. Little is known about the effectiveness of these measures for the diversity of different species groups, especially in interaction with the surrounding landscape context. Within the framework of the presented dissertation, various measures to enhance biodiversity were investigated using different organism groups in vineyards. The main part of this work is based on a field study in which organic and conventional management were compared. For this purpose, 15 pairs of organically and conventionally managed vineyards along a gradient of landscape complexity in Rhinehessen were chosen. The effects of management system, landscape context and inter-row vegetation structure on different species groups within vineyards were compared. Studied groups included entomopathogenic fungi in the soil, soil-dwelling spiders and carabid beetles as well as flying, cavity-nesting solitary bees and wasps. In an additional experiment, four different soil treatments and their effects on carabid beetles and their weed predation potential were compared in two consecutive years. Therefore, four experimental plots each were installed in nine additional vineyards in Rhinehessen. For these vineyards, landscape structure and inter-row vegetation cover was also characterised. Overall, each of the investigated species groups benefited from different measures and landscape or vegetation structure. Organically managed vineyards did not show a general increase in biodiversity, even though their soils had higher organic matter contents on average and their vegetation cover offered more floral resources. Entomopathogenic fungi were found to be particularly well adapted to increased copper levels in the soil. Soil copper contents tended to be higher under organic management. Solitary bees and soil-dwelling spiders profited from organic farming. Enhanced landscape complexity, i.e. the connectivity of semi-natural habitat elements and the area covered by them was particularly beneficial for solitary bees and spiders. An increasing proportion of area covered by annual crops in the vicinity of vineyards had a negative effect on carabid beetles and solitary wasps. While the wasps benefited from dense inter-row vegetation cover, carabid beetles preferred sparse vegetation cover. Similarly, more intensive tillage regimes did not have a negative effect on them. It should be emphasized that all the sampled vineyards - whether organically or conventionally managed - hosted species of conservation concern from all investigated groups. With a diverse mixture of landscape structures as well as a variation of management strategies and soil and vegetation covers within fields, viticultural landscapes can contribute significantly to the protection of agrobiodiversity.}, language = {en} } @phdthesis{Neumann2020, author = {Neumann, Lena}, title = {Improving the apple carbon balance model MaluSim by integrating and testing water deficit and fruit drop effects}, volume = {2020}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-139}, school = {Hochschule Geisenheim University}, pages = {162}, year = {2020}, abstract = {Apple (Malus x domestica Borkh.) is the major tree fruit in Germany, but there still exist major uncertainties in commercial apple production. Thinning has been practiced for many years and is an essential part for successful apple production, but is still an unpredictable part with large variations from year to year and even within years. Another uncertainty for apple growers is the need of apple trees for adequate water supply. Due to the advancing climate change apple growers are uncertain whether additional irrigation will be necessary during the establishment phase of young apple trees. Therefore, to facilitate these decisions in future, the motivation of this study was to acquire a universal apple model to be used in Germany and Central-Europe. The apple carbon-balance model MaluSim which has been developed in the USA was chosen as a basis. At first, the model has been parameterized for German growing conditions and first simulation runs were conducted. In comparison to the original model, the seasonal assimilate production for German standard trees was about half of the one for standard trees in the USA, while standard trees in Germany were only about one third of the size of US ones. Subsequently, the previously untested fruit growth and abscission submodel has been modified and tested. Simulated final fruit numbers were compared to counted fruit numbers of unthinned trials in Zornheim (GER), Jork (GER), Lindau (CH), G{\"u}ttingen (CH) and W{\"a}denswil (CH). The modification 'G4-4' showed good simulation results with very low deviations to actual fruit numbers. Average deviation to fruit numbers was only 3.7 \%. Results indicate that the model is able to very adequately calculate final fruit numbers of natural fruit drop of Central-European apple trees and that it could be a tool used for thinning advices. Based on published data, a new water submodel has been included into the MaluSim framework to additionally improve the model. Midday stem water potential has been used as an indicator for water status of the tree. A water stress effect on long shoot growth, respiration, and photosynthesis based on midday stem water potential was used in the water submodel. First simulation runs using the new water submodel indicate that general behavior is realistic. Modeling results generally corresponded to findings of published experimental results. The submodel is able to simulate variable intensities of water deficit effects at variable times. To study the effects of additional irrigation and water deficits on young apple orchards a field experiment was conducted during 2012 and 2013 in Geisenheim, Germany. Trees of the cultivars 'Fresco' ('Wellant®'), 'Jugala', and 'AW 106' ('Sapora®') were planted in autumn 2011 in a randomized plot design. In 2012, three irrigation treatments, CT (control treatment, only rain fed), NT (normal treatment, irrigated with 2 L/tree/day), and ET (evapotranspiration treatment, irrigation based on calculated water balance), were applied and effects on tree growth and physiology were recorded in 2012 and 2013. Besides soil moisture, water status of the trees has been recorded using predawn and midday stem water potential measurements. In both years, amounts of precipitation were higher than the 30-year average for the site, with 2013 being wetter than 2012. Between treatments, statistically significant differences developed in both seasons, but were less profound in 2013. In 2012, vegetative growth recorded in NT and ET was statistically significantly higher than in CT for all cultivars. In the wetter season 2013, similar tendencies evolved. But only in 'Jugala' and 'Fresco' long shoot growth and wood surface area was significantly higher, while for 'AW 106' differences in long shoot growth were not statistically significant. Similar results were obtained for the first harvest in 2013. Light interception and calculated leaf area, measured in 'Fresco', was significantly lower in CT trees (2012: 17.4 \%; 2013: 24.9 \%) compared to ET (2012: 26.3 \%; 2013: 42.1 \%) and NT (2012: 24.2 \%; 2013: 38.3 \%), in both years. Additionally, differences between CT and the two irrigated treatments were found for leaf gas exchange rates during the seasons. A relationship between midday stem water potential and leaf gas exchange has been confirmed. Grouping of photosynthesis measurements according to midday stem water potentials led to statistically significant differences between groups. Photosynthesis started to decrease between -1 and -1.5 MPa. In conclusion, the results show that although both years have even been wetter than usual, the additional irrigation was highly beneficial for tree growth and had a positive effect on orchard establishment. This effect is supposed to be considerably higher in drier years.}, language = {en} } @phdthesis{Doerr2020, author = {D{\"o}rr, Oliver Sebastian}, title = {Influence of artificial sunlight from a microwave plasma lamp on morphology and secondary metabolism of horticultural plants}, volume = {2020}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-122}, school = {Hochschule Geisenheim University}, pages = {158}, year = {2020}, abstract = {Light is one of the most important abiotic factors for plant physiological processes. In addition to light intensity, the spectral quality of light can also influence the plant morphology and the content of secondary metabolites. In the horticultural industry, artificial light is used in to enable year-round production of herbs, ornamental plants and vegetables in winter terms. Until today, discharge lamps like high-pressure sodium (HPS) lamps, emitting predominantly orange and red light and high amounts of infrared radiation, are the most common lamp systems in greenhouses. In the last decades, light-emitting diodes (LEDs) emerged as an efficient alternative light source. LEDs have the advantage of distinct adjustments to the light spectrum. For a usage in horticultural industry LEDs are often too expensive. Furthermore, reduced plant growth can occur due to incorrectly adjusted light spectra and lower leaf temperatures caused by the lack of infrared radiation. In a research project (LOEWE, funding no. 487/15-29) funded by the Hessen State Ministry of Higher Education, Research and Arts, Microwave plasma lamps (MPL) were tested as new light sources for horticultural industry and plant research. The electrodeless lamp systems emit light in similar properties like sun light. The aim of the study was to determine the influence of artificial sunlight of the MPL on the accumulation of secondary metabolites, plant architecture and plant physiology of three different species (coleus, basil and potted roses). The MPL was compared with other light systems such as commercial HPS lamps, LEDs or ceramic metal halide lamps (CDM). In addition to morphological parameters such as plant height, internode length or fresh and dry weight, the phenolic content of leaves grown under the respective light sources were examined. Overall an increased far-red light content in the emission spectra of the MPL showed high influence on the plant architecture which was observed in all three plant species. Artificial sunlight from MPL induced stem elongation in coleus and basil plants, compared to the other tested light sources. In potted roses a reduced branching degree was observed under MPL light compared to HPS grown plants. In addition to the impact of far-red light also the blue light content of the emission spectra was found to be a strong influencing factor for plant physiological processes. A positive correlation between blue light content and leaf thickness was determined in coleus cultivated under MPL, LED, HPS and CDM lamps. Low blue light content in HPS emission spectra resulted in shade-adapted leaves with low photosynthetic capacity and susceptibility to high irradiances. Blue light was assumed to increase phenolic metabolites in basil and rose leaves. Furthermore, the different light treatments resulted in an alteration of the composition of essential oils of basil. Experiments with coleus plants demonstrated that besides light color also the infrared radiation, had an influence on secondary metabolites by causing different leaf temperatures. Coleus plants grown with MPL showed the lowest content of phenolic compounds such as rosmarinic acid per dry weight. Infrared radiation resulted in a faster plant development indicated by increased biomass production and higher leaf formation rate as observed in coleus and basil plants. The results obtained in this study show that the influence of leaf temperature should always be considered when comparing different lamp systems. Especially when LEDs are compared to discharge lamps an overestimation of light color can be a consequence since also infrared radiation influences the content of phenolic compounds and plant growth.}, language = {en} } @phdthesis{Hessdoerfer2015, author = {Heßd{\"o}rfer, Daniel}, title = {Untersuchungen zur kontinuierlichen Wasserpotentialmessung sowei des Einflusses verschiedener Tropfbew{\"a}sserungssysteme auf die generative und vegetative Wuchsleistung von Vitis vinifera (cv. Silvaner)}, volume = {2015}, edition = {1. Auflage}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-117}, school = {Hochschule Geisenheim University}, pages = {XV, 144 S.}, year = {2015}, abstract = {In den Jahren 2011 und 2012 wurde im Versuchsfeld am „Th{\"u}ngersheimer Scharlachberg" des Sachgebietes Weinbaumanagement der Bayerischen Landesanstalt f{\"u}r Weinbau und Gartenbau bei der Rebsorte Silvaner kontinuierlich das Wasserpotential mittels temperaturkorrigierter In-situ-Psychrometer gemessen. Ziel der durchgef{\"u}hrten Arbeiten war es, die Wasserpotentialdynamik von Reben an ihrem nat{\"u}rlichen Standort und die Pflanzenreaktion auf wechselnde Witterungseinfl{\"u}sse zu untersuchen. Zus{\"a}tzlich wurde die Ver{\"a}nderung der hydraulischen Leitf{\"a}higkeit der Gesamtpflanze bei unterschiedlichem Evaporationsanspruch und Bodenwasserstatus betrachtet. Die kontinuierliche Wasserpotentialmessung an Reben wurde in den Versuchsjahren am Rebstamm und an traubentragenden einj{\"a}hrigen Trieben durchgef{\"u}hrt. Dabei konnte festgestellt werden, dass sich das Messgewebe des Triebes besser eignet, um das Wasserpotential {\"u}ber einen l{\"a}ngeren Zeitraum kontinuierlich mittels In-situ-Psychrometer an Reben zu ermitteln. Anhand der Tagesg{\"a}nge ließen sich deutliche Beziehungen zwischen der Wasserpotentialdynamik und den verschiedenen Witterungsfaktoren feststellen. So hatten die beiden Faktoren VPD und Temperatur den gr{\"o}ßten Einfluss auf das Stammwasserpotential der Reben. Dementgegen wurde zwischen der Globalstrahlung und dem Stammwasserpotential kein Zusammenhang ermittelt. Der engste kurvilineare Zusammenhang wurde jedoch zwischen dem VPD und dem Wasserpotentialgradienten, der treibenden Kraft f{\"u}r den Transpirationsstrom der Pflanze, ermittelt. Der Einfluss des Bodenwasserstatus auf die Stammwasserpotentialdynamik der Reben war relativ gering. Große Unterschiede im Wasserpotentialverlauf des Tages wurden durch eine Rebenbew{\"a}sserung induziert. Demnach f{\"u}hrte der verbesserte Wasserstatus zu einem reduzierten Potentialgradienten der bew{\"a}sserten Reben zur Aufrechterhaltung der Transpiration im Vergleich zu den nicht bew{\"a}sserten Reben. In den Jahren 2011 bis 2013 wurde Exaktversuch zur Pr{\"u}fung der Auswirkungen einer Rebenbew{\"a}sserung mit bestimmten Bew{\"a}sserungsschwellenwerten durchgef{\"u}hrt. Ziel dieses Feldversuchs war es, den Einfluss verschiedener Bew{\"a}sserungsmethoden und Bew{\"a}sserungsintensit{\"a}ten auf die generative und vegetative Wuchsleistung der Rebsorte Silvaner zu untersuchen. Das versuchstechnisch vorgegebene Bew{\"a}sserungsmanagement der Varianten moderate {\"U}berflurbew{\"a}sserung, intensive {\"U}berflurbew{\"a}sserung, moderate Unterflurbew{\"a}sserung und intensive Unterflurbew{\"a}sserung wurde mittels des fr{\"u}hmorgendlichen Wasserpotentials exakt gesteuert. Gleichzeitig wurde innerhalb des Versuchsfeldes der Verlauf der Bodenfeuchtigkeit innerhalb der Kontrollvariante mittels der FDR-Technologie gemessen. Zus{\"a}tzlich wurde nach der Lese von jeder Variante das C12 / C13 Stabilisotopenverh{\"a}ltnis, der δ13C-Wert, im Mostzucker ermittelt. Um den Einfluss der verschiedenen Bew{\"a}sserungsintensit{\"a}ten und -methoden auf die generative und vegetative Wuchsleistung zu untersuchen, wurden die erzielten Traubenertr{\"a}ge, Mostgewichte (°Oe), Mosts{\"a}uren und Schnittholzertr{\"a}ge bestimmt. Der Bew{\"a}sserungsversuch zeigte auf, dass eine Zusatzbew{\"a}sserung bei der Rebsorte Silvaner einen starken Einfluss auf das vegetative Wachstum aus{\"u}bte und kein signifikanter Einfluss auf die erzielten Traubenertr{\"a}ge festzustellen war.}, language = {de} } @phdthesis{Linck2019, author = {Linck, Holger}, title = {Diagnosis, Transmission, and Management of Phytoplasmas Infecting Rubus Species}, volume = {2019}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-102}, school = {Hochschule Geisenheim University}, pages = {XII, 122}, year = {2019}, abstract = {Phytoplasmas ('Candidatus Phytoplasma') are plant-pathogenic bacteria that colonize the phloem of their host plants and can cause diseases in more than 700 plant species world-wide, including many economically important crops, ornamentals, and forest trees. They are spread by phloem-feeding insect vectors, vegetative propagation (grafting or production of cuttings), or plant parasitic dodder species of the genus Cuscuta. In Rubus species, phytoplasmas are associated with a disease referred to as Rubus stunt. Symptoms include stunting, witches' broom, small leaves, short internodes, enlarged sepals, phyllody, flower proliferation, and fruit malformations. As Rubus species are usually propagated vegetatively and the period of latency can be up to one year, the commercial production of planting material in plant nurseries can play a major role in the spread of Rubus stunt in addition to its only known insect vector, the leafhopper Macropsis fuscula. Furthermore, phytoplasmas usually occur in Rubus plants at concentrations too low for regular PCR to detect their DNA in plants and nested PCR is too time consuming for routine screening and prone to carry-over contamination. Hence, a fast, sensitive, and reliable molecular detection method for phytoplasmas in Rubus species is of major importance to stop the spread of this disease. Therefore, a multiplex TaqMan qPCR assay for the detection of Rubus stunt phytoplasmas was developed in this thesis, which provides an efficient tool for the screening of Rubus mother plants. This qPCR assay was subsequently used in a screening of putative insect vectors of Rubus stunt phytoplasmas in raspberry plantations in southern and northern Germany. A total of 4868 hemipteran insects were sorted, identified to family, genus, or species level and 597 DNA extracts, including pooled samples representing all identified insects, sampling locations, and sampling dates, were analyzed for phytoplasma DNA. With only seven sampled individuals of M. fuscula the occurrence of the only known vector for Rubus stunt phytoplasmas was low. DNA extracts from 18 samples were positive for phytoplasma DNA, among them species from the genera Euscelidius, Macrosteles, Euscelis, Anaceratagallia, and Psammotettix. Furthermore, the susceptibility of four raspberry cultivars to Rubus stunt after artificial graft inoculation was investigated. While graft inoculation was verified to be a practical tool for artificial phytoplasma inoculation in raspberries, assessing the disease severity of Rubus stunt proved to be difficult. All four raspberry cultivars used in this experiment ('Autumn Bliss', 'Glen Ample', 'Polka', and 'Tulameen') were successfully colonized by phytoplasmas. The efficacy of heat therapy with subsequent tissue culture to eliminate phytoplasmas from infected raspberry and blackberry plants was also evaluated. All previously infected raspberry and blackberry plants were tested negative for the presence of phytoplasma DNA after this procedure. Therefore, this method is suitable as an important step during the production of healthy mother plants and nuclear stock material in order to secure the production of healthy planting material. In conclusion, a fast and reliable molecular detection assay for routine diagnostics of phytoplasmas in Rubus species was developed and applied in experiments investigating putative insect vectors of Rubus stunt phytoplasmas, the susceptibility of different raspberry cultivars, and the efficacy of heat therapy coupled with tissue culture. The results of these trials can now be incorporated into disease management strategies for Rubus stunt.}, language = {en} } @phdthesis{BouNader2018, author = {Bou Nader, Khalil}, title = {Grapevine Age: Impact on Physiology and Berry and Wine Quality}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-88}, school = {Hochschule Geisenheim University}, year = {2018}, abstract = {Vine age and its relation to the quality of the wine are topics of recurring interest, both scientific and economic. Consumers and actors in the wine sector seem to agree on the ability of old vines to produce wines of superior character. Despite ongoing research, the validity of this point of view remains debated and questions about the mechanisms through which old vines would end up with superior quality wines remain numerous. To try to answer them, the impact vine age on physiology, tolerance to water stress, and berry and wine quality were studied in an experimental vineyard planted with Vitis vinifera L. cv. of identical genetic material (Riesling Gm 239 grafted on 5C Teleki) but planted in different years. In 2014 and 2015, the vines planted in 2012 had not yet reached their full potential and had a significantly lower vegetative productivity and yield than the vines planted in 1995 and 1971. Moreover, the vines planted in 2012 were not subjected to the same grass treatment as older vines during this period to prevent excessive competition during establishment. The lower capacity of these vines and the absence of cover crop led to greater exposure of clusters to light and greater nitrogen accumulation, which resulted in a higher concentration of amino acids, monoterpenes, norisoprenoids, and flavonols in 2014 and 2015. In the following years (2016 and 2017), the yield and pruning weight of these vines, as well as their berry composition, were comparable to those of the older vines. The parameters of technological maturity (° Brix, total acidity and must pH) were not significantly affected by vine age. Vines planted in 1995 and 1971 showed similar physiological characteristics throughout the study with the exception of a higher incidence of esca syndrome in the older group. This disease was responsible for the decline in the total yield of vines planted in 1971, but individual yield per vine was equivalent for both groups. Sensory and chemical analyzes were conducted in 2017 on wines from previous vintages. The wines of the youngest vines were associated with aromas of ripe fruit and the kerosene aroma that is typical of Riesling. These wines were also identified by higher concentrations of potential monoterpenes and norisoprenoids and volatile sulfur compounds in 2014 and 2015 only. The sensory and chemical profiles of wines from vineyards planted in 1995 and 1971 were dependent on the vintage but not on the age of the vines. The wine profiles produced in 2016 were overlapping for the three age groups. The works described in this thesis manuscript are unique, particularly because the vineyard in which they were conducted was designed specifically to study the effect of the age of the vine under comparable environmental conditions. Once the youngest vines reached their fruiting potential and were conducted in the same way as the older vines, their productivity, the composition of their berries and the quality of the wines they produce converged with those of the two other groups. More interestingly, vines aged 19 and 43 years behaved similarly throughout the study and resulted in wines comparable in terms of sensory analysis, which goes against the an idea that the older vines produce wines of a different profile. Previous studies have shown that the productivity of the vines, whatever their age, could be explained by the wood reserves and the size of the trunk. To have a better idea of differences linked to reserves, the structure-from-motion with multi-view stereo-photogrammetry (SfM-MVS) method was tested to measure trunk thickness and volume. The technique, which allows the creation of scaled, georeferenced 3D models based on photographs, was able to produce accurate models of field-grown grapevine trunks.}, language = {en} }