Browsing by Subject "Soybean"
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Publication Advancing soybean adaptation to Central European growth conditions with novel breeding tools(2020) Jähne, Felix; Würschum, TobiasAccording to the European Soy Monitor 2018 (European Soy Monitor, 2018), there is a wide discrepancy in the EU between market demands and general sustainability aims regarding soybean products. Europe needs to take action, if it wants to maintain its protein demands and at the same time requests a reduction in the destruction of globally important tropical and subtropical ecosystems. One step towards more sustainable soybean products lies in the increase of domestic production which has the potential to decrease soybean imports from areas of unsustainable cultivation. An augmented EU production of soybeans can be achieved for example by increasing the yield potential of soybeans in areas where successful cultivation already takes place or by expanding the cultivation area to more northern parts of Central Europe. Breeding for new, improved and adapted soybean cultivars that meet those terms, is a key activity towards that aim. This dissertation elucidates three different ways how the adaptation of soybeans to the climatic and photoperiodic conditions of Central Europe can be assisted and even accelerated: 1) By using off-season climate-controlled LED chambers to enable a speed breeding single seed descent approach. A 10 h light regime, rich in blue and deprived of far-red light emission is capable to significantly reduce and synchronise the generation time of soybeans. It was possible to shorten the life cycle for a panel of 8 soybean cultivars from different maturity groups to 77 days. This allows several generations of soybeans to be grown within one year. For the short day crops rice and amaranth on the other hand, different light quality parameters were favoured. In those crops mean flowering time was accelerated when far-red light was included in the light protocol. This underlines the importance of a crop-specific light regime in order to realise the full potential of LED-based speed breeding single seed descent. 2) By including experiments in climate-control chambers in combination with molecular tools (i.e. genomic prediction) to advance cold tolerance in soybeans. This quantitatively inherited key trait is necessary to adapt soybeans to colder regions and consequently extend growing areas of this crop to higher latitudes in Europe. In the biparental soybean population Merlin × Sigalia (103 recombinant inbred lines) three QTL for cold tolerance during pod onset were found on chromosomes 7, 11 and 13. The relatively small proportion of genotypic variance for this trait explained by these QTL underlines the quantitative nature of cold tolerance. Genomic prediction was shown to be a promising approach to select for cold stress tolerance. Scenarios with different test set sizes and prediction models were evaluated. In scenarios with smaller test set sizes prediction accuracies increased if known and confirmed QTL were included in the prediction model. 3) By incorporating citizen science into the breeding process. The citizen science project ‘1000 Gärten’ from 2016 approached this topic. Phenotypic data from soybean cultivars and breeding lines were collected by citizen scientists in 2492 gardens throughout Germany which generated a unique dataset. Among many other results this study was able to show that in 2016 and within the early maturity segment of soybeans the factor temperature influenced flowering and maturity to a higher degree than photoperiod although day length differed by over an hour between the north and the south of Germany during the time of flowering. It was shown that this admittedly challenging tool can realise a significant impact not only regarding the possibility of a highly multi-environmental screening of breeding material but also by connecting plant breeding, agriculture and potential future costumers in order to raise awareness and acceptance of a crop in larger parts of the society - a factor that may not be highlighted enough when a new crop is introduced to our agriculture. These approaches should not be seen as an alternative to classical plant breeding, but rather considered as valuable additional tools that can contribute to conventional breeding of soybeans, as well as other crops. If applied, the presented tools may assist plant breeding to pave Europe’s way towards a greener and more sustainable future that is urgently needed.Publication Analysis of phytotoxicity and plant growth stimulation by multi-walled carbon nanotubes(2016) Zaytseva, Olga; Neumann, GünterNanotechnology is a rapidly expanding area of science and technology, which has gained a great interest due extraordinary properties of nanomaterials with numerous potential fields for practical application. Meanwhile, carbon nanotubes (CNTs) are among the ten most-produced engineered nanomaterials worldwide with applications in automotive industry, building and construction, electronics, and many other industrial sectors, showing also a great potential for integration into environmental and agricultural applications. However, during the last decade it has been demonstrated that nanomaterials can exert significant and extremely variable effects also on living organisms. In higher plants, both, positive and negative responses on growth and development have been reported but the related mechanisms are still not entirely understood. This study presents a systematic assessment of CNT effects on representative crops under standardized conditions with special emphasis on interactions with plant nutrition. After the introductory background (Chapter 1), presenting a comprehensive literature review on carbon nanomaterials with special emphasis on plant responses, environmental and agricultural applications, Chapter 2 describes the impact of selected multi-walled carbon nanotubes (MWCNTs) on seed germination and early seedling development of different crops (soybean−Glycine max, maize−Zea mays, and common bean−Phaseolus vulgaris). In face of highly variable plant responses to CNT treatments reported in the literature, the study was designed as a systematic analysis under standardized growth conditions, dissecting the effects of one single type of MWCNTs, depending on plant species, MWCNT dosage, duration of exposure to MWCNT treatments, and plant-developmental stage, including imbibition, germination and seedling development. Short-term seed treatments (36 h) with MWCNTs reduced the speed of water uptake particularly by soybean seeds, associated with an increased germination percentage and reduced formation of abnormal seedlings. However, during later seedling development, negative effects on fine root production were recorded for all investigated plant species. Inhibition of root growth was associated with reduced metabolic activity of the root tissue and a reduction of nitrate uptake, which could be mainly attributed to the smaller root system. The results demonstrated that even under standardized growth conditions largely excluding external factors, plant responses to MWCNT exposure exhibit differences, depending on plant species but also on the physiological status and the developmental stage of individual plants. Soybean was selected as a model plant for further studies since both, positive and negative effects of the same dose of MWCNTs (1000 mg L-1) could be observed even in the same individual plants. Chapter 3 investigates effects of short-term soybean seed exposure (36 h) to MWCNTs on seedling development, depending on the nutrient availability of the substrate. At 8 DAS stunted growth and poor fine root production were first detectable in seedlings germinating on moist filter paper without additional nutrient supply. This effect was preceded by reduced metabolic activity of the seedling tissues detectable by vital staining already at 2 DAS. Root growth inhibition was a long-lasting effect, detectable in soil culture up to 38 DAS. More detailed investigations revealed zinc (Zn) deficiency as a major growth-limiting factor. The growth of affected soil-grown plants was recovered by foliar application of ZnSO4 or by cultivation in nutrient solution supplied with soluble ZnSO4. A more detailed investigation of the physiological mechanisms related with the inhibitory effects of MWCNTs on plant growth is presented in Chapter 4. Oxidative stress was identified as a major factor determining MWCNT-induced root growth inhibition in soybean, demonstrated by recovery of root development after external supplementation with antioxidants. Induction of oxidative stress by MWCNT application was detectable already after the 36 h imbibition period particularly in the tips of the radicle as indicated by accumulation of superoxide anions, reduced triphenyltetrazolium chloride vital staining, and induction of superoxide dismutase activity. The expression pattern of the oxidative stress indicators coincided with preferential accumulation of MWCNTs in the cells of the root tip and was reverted by external application of proline as antioxidant. MWCNT-induced plant damage could be reverted by external supplementation of micronutrients (Zn, Cu, Mn) as important cofactors for various enzymes involved in oxidative stress defense (SOD, biosynthesis of antioxidative phenolics). Accordingly, SOD activity increased in seedling roots after Zn supplementation. During germination, the CNT treatments inhibited particularly the Zn translocation from the cotyledons to the growing seedling, and CNTs exhibited a selective adsorption potential for Zn and Cu, which may be involved in internal immobilization of micronutrients. Therefore, this study demonstrated for the first time that phytotoxicity of CNTs is linked with disturbances of micronutrient homeostasis during seedling development. Implications for environmental phytotoxicity assessment of MWCNTs and their potential applications in agriculture are discussed in a final overview presented in Chapter 5.Publication Assessment of phenotypic, genomic and novel approaches for soybean breeding in Central Europe(2022) Zhu, Xintian; Würschum, TobiasSoybean is the economically most important leguminous crop worldwide and serves as a main source of plant protein for human nutrition and animal feed. Europe is dependent on plant protein imports and the EU protein self-sufficiency, which is an issue that has been on the political agenda for several decades, has recently received renewed interest. The protein imports are mainly in the form of soybean meal, and soybean therefore appears well-suited to mitigate the protein deficit in Europe. This, however, requires an improvement of soybean production as well as an expansion of soybean cultivation and thus breeding of new cultivars that combine agronomic performance with adaptation to the climatic conditions in Central Europe. The objective of this thesis was to characterize, evaluate and devise approaches that can improve the efficiency of soybean breeding. Breeding is essentially the generation of new genetic variation and the subsequent selection of superior genotypes as candidates for new cultivars. The process of selection can be supported by marker-assisted or genomic selection, which are both based on molecular markers. A first step towards the utilization of these approaches in breeding is the characterization of the genetic architecture underlying the target traits. In this study, we therefore performed QTL mapping for six target traits in a large population of 944 recombinant inbred lines from eight biparental families. The results showed that some major-effect QTL are present that could be utilized in marker-assisted selection, but in general the target traits are quantitatively inherited. For such traits controlled by numerous small-effect QTL, genomic selection has proven as a powerful tool to assist selection in breeding programs. We therefore also evaluated the genomic prediction accuracy and found this to be high and promising for the six traits of interest. In conclusion, these results illustrated the potential of genomic selection for soybean breeding programs, but a potential limitation of this approach are the costs required for genotyping with molecular markers. Phenomic selection is an alternative approach that uses near-infrared or other spectral data for prediction instead of the marker data used for its genomic counterpart. Here, we evaluated the phenomic predictive ability in soybean as well as in triticale and maize. Phenomic prediction based on near-infrared spectroscopy (NIRS) of seeds showed a comparable or even slightly higher predictive ability than genomic prediction. Collectively, our results illustrate the potential of phenomic selection for breeding of complex traits in soybean and other crops. The advantage of this approach is that NIRS data are often available anyhow and can be generated with much lower costs than the molecular marker data, also in high-throughput required to screen the large numbers of selection candidates in breeding programs. Soybean is a short-day plant originating from temperate China, and thus adaptation to the climatic conditions of Central Europe is a major breeding goal. In this study, we established a large diversity panel of 1,503 early-maturing soybeans, comprising of European breeding material and accessions from genebanks. This panel was evaluated in six environments, which revealed valuable genetic variation that can be introgressed into our breeding programs. In addition, we deciphered the genetic architecture of the adaptation traits flowering time and maturity. Taken together, the findings of this study show the potential of several phenotypic, genomic and novel approaches that can be integrated to improve the efficiency of soybean breeding and thus hold great promise to assist the expansion of soybean cultivation in Central Europe through breeding of adapted and agronomically improved cultivars.Publication Chances and limitations of European soybean production : market potential analysis(2016) Berschneider, JanaOverseas imports of soybeans from Brazil, the US and Argentina to Europe are increasing every year. Simultaneously, GMO farming in these countries is being expanded ever further. European farming of protein crops especially soybeans is being pushed by organizations and protein initiatives for economical and ecological reasons. In 2015 soybean acreages expanded drastically due to the additional Greening political measures which came into force. Therefore it is worth asking about the potential of a European non-GMO soybean market. The aim of this thesis was to work out the principal chances and limitations of a European soybean market under the current agricultural political conditions. Moreover, it should be discussed how many of the imported soybean commodities, of which more than 85% are from overseas, could be replaced by soybeans planted in Europe. In order to get to the bottom of the interests in this market from the perspective of the market actors, ten interviews were carried out. The result made it clear. European soybeans cannot yet compete with the overseas soybeans in terms of quantity (homogenous commodity lot sizes), price and even quality (mainly protein content). Thats why European non-GMO soybeans are not yet of high importance on the most important consumer market, which is the feed market, as large processors favor homogeneous lots and a reliably supply of commodities as to avoid volatile qualities in production. The greatest constraint comes from the limited availability of arable land in Europe as well as from a lack of early maturing soybeans that are well adapted to the European growing conditions. The restricted availability of arable land lead to a competitive situation with other cash crops such as corn, but according to the results of this thesis, soybean growing’s result in lower revenues and are therefore economical less competitive than corn. Thus, output (income) optimizing farmers under today’s conditions decide not to replace corn by soybeans. Furthermore, a limited practice experience in less experienced relatively new soybean growing regions slow down the development of a competitive European soybean market. Moreover, an insufficiently established non-GMO soybean industry hinder the market development due to difficulties of coexisting GMO and non-GMO commodities. Separated product flows in non-GMO processing plants, wholesale and collection points, are segments within the value chain which need to be further promoted for this market development. The zero tolerance regarding GMO traces in seed has been analyzed as a market barrier especially in the plant breeding industry. Thus, the thesis argued to establish a feasible GMO threshold value for seed as is already legal for food and feed.This is mentioned as a political constraint primarily, as well as too little effort towards specifically promoting a regional protein strategy, if more independence from overseas imports will be achieved. On the other hand, chances for the European soybean market are expected, as long as added value can be generated through special marketing programs, particularly trademarks. This means marketing products at higher prices according to regionality and non-GMO labelling. Therewith, a distribution of additional costs for testing and separation along the value chain could be achieved. Especially the Danube Soya Association is being described as a driving force. They mobilize market agents along the value-added chain, help to create uniform standards, test and monitors soybean commodities to be non-GMO and are finally labeled as such. In this way the non-GMO separation needs to be extended by European regulation to simplify the process to reach a European non-GMO soybean market. The consumers demand for local or organic products is constantly increasing. Consequently, non-GMO soybean components are being asked for in animal feed. A significant market opportunity for soybeans is that they are not really replaceable (in terms of quality) by any other protein crop without needing to reduce the economic efficiency of animal production. Therefore, the potential for demand is there principally. The analysis of the application of non-GMO feed shows that this is only of importance in smaller amounts in a few countries within Europe. Significant animal producing countries such as the Netherlands and Spain have no interest in non-GMO products. Thus, the intentions behind the European non-GMO soybean market, such as more independence from overseas imports, are likewise limited to specific regions of Europe. The European soybean production possibilities are economical and geographical limited and would not be able to do much more than satisfy certain consumer niches who are willing to pay the added value for non-GMO products.Publication Do we need to breed for regional adaptation in soybean? - Evaluation of genotype-by-location interaction and trait stability of soybean in Germany(2023) Döttinger, Cleo A.; Hahn, Volker; Leiser, Willmar L.; Würschum, TobiasSoybean is a crop in high demand, in particular as a crucial source of plant protein. As a short-day plant, soybean is sensitive to the latitude of the growing site. Consequently, varieties that are well adapted to higher latitudes are required to expand the cultivation. In this study, we employed 50 soybean genotypes to perform a multi-location trial at seven locations across Germany in 2021. Two environmental target regions were determined following the latitude of the locations. Adaptation and trait stability of seed yield and protein content across all locations were evaluated using Genotype plus Genotype-by-Environment (GGE) biplots and Shukla’s stability variance. We found a moderate level of crossing-over type genotype-by-location interaction across all locations. Within the environmental target regions, the genotype-by-location interaction could be minimised. Despite the positive correlation (R = 0.59) of seed yield between the environmental target regions and the same best-performing genotype, the genotype rankings differed in part substantially. In conclusion, we found that soybean can be grown at a wide range of latitudes across Germany. However, the performance of genotypes differed between the northern and southern locations, with an 18.8% higher mean yield in the south. This in combination with the observed rank changes of high-performing genotypes between both environmental target regions suggests that selection targeted towards environments in northern Germany could improve soybean breeding for those higher latitude regions.Publication Einfluss von Anbauverfahren und Umweltfaktoren auf Ertrag, Qualität und agronomische Eigenschaften von Soja (Glycine max L. Merrill)(2021) Sobko, Olena; Gruber, SabineWith a crude protein content of approximately 40% and a crude fat content of approximately 20% in the seeds, soybean (Glycine max L. Merril) is one of the worlds most important crops with a wide range of uses. The high-quality soybean protein is an important component of animal feed in dairy and meat production. Soybean oil is often used in human nutrition, and with increasing vegetarian or vegan diets, protein-rich foods made from soybean are in high demand. In practical farming, soybean is a beneficial crop in crop rotations because it can fix atmospheric nitrogen through symbiosis with rhizobia, making the plant self-sufficient in nitrogen supply. Since soybean cultivation has no tradition in Germany, optimization of the cultivation technique is required. The present work is about the elaboration of efficient cultivation techniques for soybean in Germany. In three publications, based on three multi-year as well as multi-location and orthogonal field trials, the effects of sowing density and sowing system on yield, protein, and oil content as well as on agronomic properties of soybean are investigated in several varieties from different maturity groups. In addition, the effects of temperature, precipitation and solar radiation on yield, oil content, and protein content have been investigated to identify potential locations for specific production priorities. In the first publication (published in Agronomy Journal MDPI), the results from trials over two years and two locations in southern Germany with four soybean varieties of different maturity groups (00, 000) and growth types with either drill seeding (row spacing 14 cm) or precision seeding (row spacing 28 cm) are presented. To answer the question of which seeding method is more efficient, the following characteristics have been investigated, namely seed yield and yield structure, protein and oil content, LAI, plant height, height of the first pod set, lodging, and nodule numbers. The sowing system did not significantly affect the tested traits, and there was little difference in yield and qualities (seed yield: 3.6 t ha-1 DM, protein content: 40.9 % DM, oil content: 18.8 % DM for drill seeding; seed yield: 3.8 t ha-1 DM, protein content: 40.1 % DM, oil content: 19.1 % DM for precision seeding). These results are very helpful for soybean producers, because they do not need to invest in new sowing technique but can sow with sowing machines which are already available on the farm. The second publication (published in Plant, Soil and Environment) is about the effects of sowing density of soybean with four varieties of maturity groups 00 and 000. Four sowing densities (30, 50, 70, and 90 seeds m-2) were tested over two years and two locations in southern Germany. The lowest seed yield (3.2 t ha-1 DM was obtained at a sowing density of 30 seeds m-2 and the highest at 90 seeds m-2 (4.4 t ha-1 DM). The 00 varieties (3.6 t ha-1 DM) were higher yielding than the 000 varieties (3.4 t ha-1 DM). Sowing density did not affect seed quality characteristics. Plants were more susceptible to lodging with increasing sowing density. The lowest pod set was 4 cm higher at a sowing density of 90 seeds m-2 (13.4 cm) than at 30 seeds m-2 (9.4 cm). Increasing sowing density could reduce yield losses due to threshing because the height of the first pod set was increased at high sowing densities. Consequently, the optimum soybean seed rate would be between 50 and 70 seeds m-2 for 00 and 000 varieties at the tested locations and similar regions in Germany. In the third publication (published in Agronomy Journal MDPI), the influences of environmental factors on yield, protein and oil content, and protein and oil yield of soybean in Germany have been investigated. In the two-year field trials, 13 soybean varieties from maturity groups 00 and 000 were tested at several locations across Germany (four in 2016 and five in 2017). The 000 varieties were less sensitive to environmental factors compared to the 00 varieties. Regardless of maturity group, high solar radiation and appropriate precipitation tended to increase seed yields (r seed yield / solar radiation = 0.32 and r seed yield / solar radiation = 0.33). High temperatures at maturity reduced the productivity but provided slightly higher protein contents in 000 varieties (r protein content / CHU at maturity = 0.23). The locations that are not at risk for water stress would be suitable for soybean production if protein or oil yield is the primary concern. Overall, this study indicates that a sowing density of 50-70 seeds m-2 in combination with varieties of appropriate maturity groups could promote soybean cultivation in Germany. In dry locations, a lower sowing density is advisable in contrast to locations with more precipitation. Additional costs for the adaptation of technical equipment would not be incurred, because both drill seeding and precision seeding can be applied. By matching the direction of use (protein and/or oil production) of soybean to the climatic conditions of specific regions, soybeans for food and feed can be produced in Germany with sufficient traceability for quality and food safety. Climate warming offers opportunities to extend soybean production in Germany. This thesis provides results from which recommendations can be derived that are immediately applicable in agricultural practice.Publication Exploring and modelling the influence of spectral light composition on soybean (Glycine max (L.) Merr.)(2019) Hitz, Tina; Graeff-Hönninger, SimoneThe development of soybean cultivars for the climatic conditions in Europe is an urgent need in order to increase the European production and to decrease the dependence of imported soybean. A speed breeding system can accelerate the process of developing new cultivars by growing more generations per season in climate chambers. The project MoLED-Plant aimed towards the development of a speed breeding system for soybean under LED lighting. The major objectives of this thesis were to: (i) construct a three dimensional model of an LED chamber to simulate micro-light climate, (ii) develop a functional-structural plant (FSP) model of soybean and derive a blue photon flux density (BPFD) response curve from simulations, (iii) apply the FSP model with the integrated response curve for spectral optimization, (iv) explore the influence of BPFD under constant photosynthetic photon flux density (PPFD), and (v) disentangle the influence of red to far-red ratio (R:FR) and PPFD on the shade avoidance response (SAR). The objectives were fulfilled with a combination of FSP modelling in the Growth Grammar-related Interactive Modelling Platform (GroIMP) and plant experiments under multiple spectra in LED chambers. The presented LED chamber model was the first three dimensional environment, which was developed for spectral optimizations in indoor farming using FSP modeling. Measurements performed with a spectrometer in multiple heights and orientations were compared to simulations recorded with a virtual sensor at the same locations. The model was evaluated as a tool for assessment of spectral light heterogeneity under an alternative placement of the LED modules. Applying the model can assist in choosing the best chamber design and placements of LEDs to assure homogeneous light conditions. Subsequently, static soybean plants were incorporated into the chamber model. Comparison of light simulations and measurements from below the soybean canopy in four reconstructed scenarios assured a good simulation of micro-light climate. The model was applied to simulate the effect of an increased plant density in an experiment in the chamber. The simulations of light homogeneity in the experimental setup can assist in choosing the optimal design. The developed dynamic FSP model of soybean within the chamber model represents the first FSP model with an integrated response to BPFD. The soybean model was calibrated with data from BPFD experiments. From simulations, a common response curve of internode elongation to the perceived BPFD was derived for the second and third internode. The response curve was integrated in the model and was applied for spectral optimization in a chamber scenario with an alternative high reflective bottom material. The soybean response to BPFD under constant PPFD and the influence of R:FR and PPFD on SAR was explored by designing specific spectra from LEDs. Soybean experiments were performed under six levels of BPFD (60-310 µmol m-2 s-1) and constant PPFD (400 µmol m-2 s-1). Plant height and biomass decreased, leaf mass ratio increased and the ratio of stem biomass (internode plus petiole) translocated to the internode decreased under high BPFD. Three soybean cultivars were grown under nine light treatments to disentangle the effect of R:FR and PPFD. Internode elongation responded mainly to low PPFD with an additive effect from low R:FR, whereas petiole elongation was influenced to a great extent by low R:FR. In the context of SAR, petiole elongation can be seen as the main response to the threat of shade (high PPFD and low R:FR) and both petiole and internode elongation as the response to true shade (low PPFD and low R:FR). This thesis showed how PPFD, BPFD and R:FR work both independently, antagonistically and synergistically on the physiology and morphology of soybean. The increased insight in these responses can e.g. support crop breeding and spectral optimization in indoor farming. Furthermore, interesting and important objectives for future research were identified. These experiments should include physiological measurements for a deeper understanding of interactions and underlying mechanisms. Spectral optimization of indoor farming depends on the purpose of the production. For instance, a high BPFD of 260 µmol m-2 s-1 was optimal for speed breeding, whereas an intermediate BPFD would be preferable to increase biomass. Comprehensive investigation of spectral influence on plant physiology and morphology is necessary to fully utilize the spectral flexibility of LED lighting. The developed FSP model of soybean in a virtual LED chamber represents an important step towards utilizing the advantages of FSP modelling by simulation of a wide variety of scenarios. The model can be adjusted or extended depending on the purpose of the model. It can be calibrated for other crop species and the setting of the chamber dimensions can be changed.Publication From greenhouse to field practice : herbicide resistance detection using chlorophyll-fluorescence-imaging technology(2017) Wang, Pei; Gerhards, RolandAll over the world, herbicide resistance has developed to one of the most important barriers in weed control, making the implementation of the weed control strategy more complicated. There is an intense need for a rapid, cheap and reliable method to conduct in field detection of herbicide resistant weed populations. In the current thesis with the use of chlorophyll fluorescence imaging technology, such a method is implemented and tested in field conditions. A series of experiments were designed and carried out. The data gathered from these experiments were compiled under three paper articles. Paper 1. A greenhouse experiment was conducted to verify if the parameter, Maximal Photosystem II Quantum Yield (Fv/Fm), could possibly indicate the herbicide efficacy. The chlorophyll-fluorescence-imaging sensor, Weed PAM®, was selected for the measurements. In the first part it was investigated if the Fv/Fm value could differentiate between herbicide sensitive and resistant plants. In the second part two important abiotic stress factors were tested if they affected the Fv/Fm value. I) Six herbicides were tested on herbicide sensitive and resistant Alopecurus myosuroides populations; II) Water shortage and nitrogen deficiency were applied on a herbicide sensitive population to observe their influence on the plants. The sensitive plants presented significantly lower Fv/Fm values than the resistant plants 3 days after treatment (DAT) for the ALS and ACCase inhibitors. On the same day, and for the same treatments the Fv/Fm values of the resistant plants were not affected and similar to the control. Appling a PS II inhibitor reduced the Fv/Fm values of both sensitive and resistant plants rapidly. Yet, sensitive and resistant plants could clearly be separated on 4 DAT based on the different Fv/Fm values. On the other hand, nitrogen deficiency did not influence the photosystem II measurements. Water shortage reduced rapidly the Fv/Fm value of the plants seven days after the application, yet at this point plant symptoms included the death of the plants. According to this experiment, the Weed PAM® sensor has proved its capability to identify the sensitive and resistant A. myosuroides populations shortly after the herbicide application. Paper 2. A verification of the above results was made under field conditions for different A. myosuroides populations and different locations. On the first part 50 populations in total including both sensitive and herbicide resistant populations were tested. The second part field experiments were conducted in ten locations around Germany over two years with the local field population mix. It was investigated if the Weed PAM® sensor could separate between herbicide sensitive and resistant A. myosuroides populations 5 DAT. The different populations were sown in a winter wheat field. Two ACCase- and three ALS- inhibitors were applied. In all herbicide treatments, Fv/Fm values of A. myosuroides were significantly lower than the untreated plants at the 5 DAT. For each location, measurements were conducted at 5 DAT. A visual measurement, to verify the result, was carried out at 21 DAT. In both cases, 95% of the plants were correctly identified as sensitive or resistant. This demonstrated the ability of the Weed PAM® sensor to conduct in field real time detection of herbicide resistant A. myosuroides populations shortly after treatment. Paper 3. Greenhouse and field experiments were carried out to investigate if the chlorophyll fluorescence of soybean plants was altered, under herbicide stress. Herbicide combinations including inhibitors of PS II, DOXP synthase, cell division and microtubule assembly were selected for different pre-emergence treatments. Herbicide combinations including inhibitors of PS II, ALS and ACCase were applied in post-emergence treatments. Chlorophyll fluorescence was measured from the emergence of soybeans until the three/four-leaf stage. Furthermore the stress effect of the different treatments on the soybean plants was determined by measuring their dry biomass. In the greenhouse, post-emergence treatments with ALS and ACCase inhibitors did not seem to induce stress on the soybean plants. As expected, it originally demonstrated low Fv/Fm values when stressed by PS II inhibitors. But the PS II system recovered soon, one week after emergence. Stress induced by other pre-emergence herbicides occurred one week after emergence and lasted longer than the stress induced by the PS II inhibitors. Dry biomass collaborated with the sensor result. Based on the current thesis, the Weed PAM® system can be an important tool in the identification of herbicide resistant weed populations, in a timely manner. It has proven its capabilities both in A. myosuroides as a weed and in soybean plants. This technology will help farmers to take more suitable weed control strategies, as well as less economic and environmental risks.Publication Nutrient seed priming improves abiotic stress tolerance in Zea mays L. and Glycine max L.(2014) Imran, Muhammad; Neumann, GünterSeed reserves are the primary source of mineral nutrients for early seedling development. ?Nutrient seed priming? is a technique in which seeds are soaked in nutrient solution and subsequently dried back to initial moisture content for storage. It is an efficient approach to increase seed nutrient contents along with priming effects to improve seed quality, germination speed and seedling establishment. Various abiotic stresses, such as sub-optimal temperature, drought, submergence and soil pH extremes can seriously affect seedling establishment and nutrient acquisition at early growth stages. This thesis focused on the role and contribution of nutrient seed priming in plant growth and nutritional status in maize and soybean under conditions of limited nutrient availability and low root-zone temperature. Protocols for nutrient seed priming with Zn, Mn, Zn+Mn, B and P were optimised for application in maize and soybean seeds (B and P priming in maize only). Optimum priming durations of 24 h (maize) and 12 h (soybean) were identified for both plant species but in instead of submerging seeds in priming solutions slow imbibition between filter papers was essential for soybean to minimise development of abnormal seedlings to avoid imbibition damage. Nutrient concentrations were calculated according to water uptake to double the natural seed reserves of the respective micronutrients and 50% increase in phosphorus. However, final uptake of the micronutrients was generally much higher (+500-1000%) while it was lower for P (+20%). In case of soybean this could be attributed to a high Zn and Mn binding capacity of the seed coat, which adsorbed up to 60% of the primed nutrients. Particularly, Zn and Zn+Mn priming stimulated plant growth in hydroponic culture systems and to a lower extent also on a soil with low availability of P, Zn and Fe. This was associated with a high shoot translocation of the primed nutrients (Zn and Mn), which was most expressed in the hydroponic culture system. Combined priming treatments with Zn and Mn were usually less effective than Zn priming alone, suggesting an antagonistic interaction. By contrast, mobility of primed B was extremely low and B priming was completely ineffective. In soil culture also P priming moderately increased shoot biomass production by 10-20 %. However the efficiency of P priming was largely limited by the high P demand of the plants. Low root zone temperature (RZT) at early spring is a limiting factor for maize production in Central and Northern Europe. Nutrient acquisition, nutrient uptake and particularly root growth are severely affected at low RZT and the consequences of these growth depressions are often not completely compensated until final harvest. Model experiments in hydroponics and soil culture revealed that maize nutrient seed priming with Zn, Mn and Fe is a promising strategy to diminish the deficiency of specific nutrients, such as Zn, Mn and also P and to maintain plant growth under low RZT stress. This was mainly attributed to significantly increased root growth and particularly fine root production in plants grown from nutrient-primed seeds. Improved net photosynthesis of primed plants was mainly related with increased leaf area and preliminary results suggest a higher tolerance to oxidative damage due to increased production of protective phenolics. Two independent field experiments under conditions of suboptimal temperatures during germination and early growth revealed an increase in grain yield of 10 ? 15 % for plants derived from Zn+Mn and Fe primed seeds. This finding demonstrates long-lasting persistence of priming effects. The molecular and physiological mechanisms behind require further investigation.Publication Phenotypic and genomics-assisted breeding of soybean for Central Europe : from environmental adaptation to tofu traits(2022) Kurasch, Alena; Würschum, TobiasSoybean (Glycine max Merr.) is one of the major crops in the world providing an important source of protein and oil for food and feed; however it is still a minor crop in Central Europe. Soybean cultivation can play an important role in a more sustainable agricultural system by increasing local and regional protein production in Europe. The demand for locally produced soybean products is still growing in Europe. The key for a successful establishment of soybean cultivation in Europe is adaptation of soybean varieties to the Central European growing conditions. For the latitudinal adaptation to long-day conditions in Central to Northern Europe, an adapted early flowering and maturity time is of crucial importance for a profitable cultivation. The key traits flowering and maturity are quantitatively inherited and mainly affected by photoperiod responsiveness and temperature sensitivity. The most important loci for an early flowering and maturity are E1-E4 and the various allelic combinations condition soybean flowering and maturity time and therefore strongly contribute to the wide adaptability (Jiang et al., 2014; Tsubokura et al., 2014; M. Xu et al., 2013). Besides the main usage as protein source for animal feeding, soybean is also a very valuable source for human consumption. Tofu is enjoying ever greater popularity in Europe, as it is one of the best sources of plant protein with additional health benefits, rich in essential amino acids, beneficial lipids, vitamins, and minerals, as well as other bioactive compounds, such as isoflavones, soyasaponin, and others, (Lima et al., 2017; Zhang et al., 2018). Thus, plant breeding has to provide not only well-adapted varieties with good agronomic and quality properties, but also provide varieties well-suited to the further processing into soymilk and tofu. Therefore, a good knowledge about the breeding target, how to assess it and how it is inherited is crucial. The conducted studies covered a broad range of aspects relevant to improve a soybean breeding program. By combining environmental analysis, E-gene analysis, genomic approaches (QTL mapping and genomic prediction), and tofu phenotyping, breeder decisions become more accurate and targeted in the way of selection thereby increasing the genetic gain. In addition, combining the results of the different aspects helps to optimize the resources of a breeding program. Increasing the knowledge about the different aspects from environment to tofu QTL enables a breeder to be more precise and focused. But the more targeted and specific, the more complex a breeding program gets, which requires adequate tools to handle all the different information in a meaningful and efficient way to enable a quick and precise breeding decision.Publication Species of the Diaporthe/Phomopsis Complex (DPC) in European soybean and establishment of quadruplex Real-Time PCR for diagnosis(2022) Hosseini, Behnoush; Vögele, RalfDiaporthe seed decay is among the most disruptive soybean diseases around the world, which cause significant yield losses and affect soybean quality. Different Diaporthe species cause this disease, while Diaporthe longicolla is considered the main causal agent. The species of this fungal complex (genus Diaporthe is also called the Diaporthe/Phomopsis Complex / DPC) have to be accurately identified for epidemiological studies of the disease and for optimal control measures. To identify the major causal agents of seed decay in Europe, DPC-damaged soybean seeds of various cultivars, that were collected from different fields in Germany, France, and Austria were tested by seed plating. 32 Diaporthe isolates could be obtained. The isolates were morphologically identified by the colors and shape of the colony, conidia dimensions, and by whether pycnidia with α- and/or β-conidia or perithecia with ascospores are formed. To corroborate morphological identification, sequences of the internal transcribed spacer (ITS), translation elongation factor 1-α (TEF1), and beta-tubulin (TUB) sequences were obtained. From the results of both morphological and molecular analyses it became clear that all isolates belong to one of the four species D. longicolla, D. caulivora, D. eres, and D. novem. The pathogenicity of all strains on soybean was tested. Molecular phylogenies were calculated and based on the above results updated species descriptions were created. This study identified these four species as the main Diaporthe pathogens for soybean in central Europe. A sensitive and accurate method for quick detection of these pathogens was developed based on multiplex real-time PCR. Specific TaqMan primer-probe sets for the four species were designed based on TEF1 sequences. The primer-probe sets were tested for specificity and efficiency using PCR products and genomic DNA from the four Diaporthe species and several other soybean pathogens. These primer-probe sets reliably distinguish the different species and they can be used to detect them in the same reaction by quadruplex real-time PCR. DNA from different soybean plant materials including healthy and infected seeds or seed coats, stems, and leaves was used to test the quadruplex real-time PCR assay. Application of the assay was extended to quantify the pathogens. Standard curves for the four species were created from serial dilutions of genomic DNA diluted with DNA from soybean tissue. An additional standard curve was created from serial dilutions of soybean DNA diluted with ddH2O. To gain the ratio of fungal DNA per plant DNA (ng/ng), DNA samples from soybean tissues can now be examined in the new assay and a parallel SYBR® Green-based real-time PCR. The assay was first applied to six soybean seed lots with putative Diaporthe contamination. In all seed lots seeds contaminated with Diaporthe species and even some seeds infected with more than one Diaporthe species were found, while other seeds were free of the pathogens. The load of fungal biomass varies strongly between individual seeds.