@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{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{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{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{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{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{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{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{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{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{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{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{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{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} }