Browsing by Subject "Protein content"

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Einfluss von Anbauverfahren und Umweltfaktoren auf Ertrag, Qualität und agronomische Eigenschaften von Soja (Glycine max L. Merrill)
(2021) Sobko, Olena; Gruber, Sabine
With 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.
Phenotypic and genotypic evaluation of yield components and nitrogen use efficiency of triticale (× Triticosecale Wittmack)
(2024) Neuweiler, Jan Eric; Würschum, Tobias
Modern agricultural systems require the use of mineral or organic fertilization to keep up with the growing demand for food, feed and recently also to replace fossil energy sources. One of the most important macronutrients to increase yields is nitrogen, mostly applied in its mineral form nitrate and ammonium. However, the biggest disadvantage of mineral fertilization is the good water solubility of these ions, leading to a high rate of fertilizers being leached out by strong rain falls. This results in the eutrophication of aquatic ecosystems and thus the destruction of these habitats. Further critical points are the entry of nitrates into the groundwater, evaporation of gaseous nitrogen compounds from agricultural soils and canopies as well as high energy consumption for the production of mineral nitrogen fertilizers and in result an increased emission of greenhouse gases. This has led to an increasingly restrictive legislation regulating nitrogen fertilization. The solution to resolve this contradiction, where yields should be as high as possible and fertilizer inputs as low as possible is not trivial. A big part of the solution will be the breeding of new, resource efficient cultivars producing high yields under limited nitrogen availability as well as special purpose cultivars, having a chemical grain composition and grain shape characteristics as demanded by the market. Triticale (× Triticosecale Wittmack), is a man-made small-grain cereal created by the hybridization of wheat (Triticum spp.) as female parent and rye (Secale spp.) as male parent. Triticale can be considered as a multi-purpose crop as its grain is used as animal feed and for the production of bioethanol as well as the whole plant is used as substrate for the production of biogas. Therefore, triticale can be regarded as an ideal crop to develop breeding strategies to tackle future challenges and to study the genetic basis of traits related to resource efficiency, as these results might also be transferred to other crops. In order to contribute to the solution of these challenges, the objectives of this thesis were to: (i) evaluate the genetic architecture of grain yield and grain quality related traits as well as of traits related to nitrogen use efficiency (NUE), (ii) evaluate long-term genetic trends resulting from breeding progress for traits of agronomic importance, (iii) assess the potential of index-selection to simultaneously improve negatively correlated grain yield and grain protein content, (iv) develop strategies for the identification of nitrogen efficient triticale genotypes and (v) assess the usefulness of marker-based selection techniques to improve grain yield and grain quality related traits as well as traits related to NUE in triticale by breeding. For this purpose, we used two panels of diverse genotypes representing the variation present in the European winter triticale germplasm pool. The PredBreed panel, comprising 1,218 genotypes tested in 2014 and 2015 at five locations and the SENSELGO panel, comprising 450 genotypes tested in 2018 and 2019 at four locations. Grain yield and protein content were evaluated in all field trials. In addition, grain shape characteristics were evaluated in the PredBreed panel. The SENSELGO panel was tested under four different nitrogen fertilization levels representing 40%, 70% 100% and 130% of the legal, site-specific maximum amount of nitrogen to be applied according to the latest fertilizer regulation of Germany to test their reaction on different nitrogen fertilization rates and to assess their NUE. Additionally starch content was measured. Our results show, that there is a continuous annual increase of 0.5 dt/ha for grain yield over the last decades. Moreover, we found that modern cultivars were able to make better use of the available nitrogen. This indicates, that modern cultivars have a better NUE compared to old cultivars due to their higher overall grain yield potential. Besides grain yield, quality and grain shape related traits are of great importance for the subsequent use of the harvested grain. For these traits it was found that modern cultivars tend to have bigger and more spherical grains with the potential to produce higher protein contents from the available nitrogen. To simultaneously select for negatively correlated grain yield and the most important quality related trait protein content, we evaluated different indices accounting for both traits, revealing that the sum of the standardized grain yield and protein content (IndexEW) led to the most balanced selection, whereas the index grain protein deviation (GPD) led to the selection of mostly low-yielding genotypes with a high protein content. The genetic architecture of all traits under investigation was found to be complex with many small- and medium-effect quantitative trait loci (QTL) and a high level of pleiotropy. Moreover, the analysis of the SENSELGO panel revealed a nitrogen dependent effect for some quantitative trait loci and the use of indices does not lead to a reduction in the complexity of the genetic architecture. These findings suggest that marker-assisted selection (MAS) methods only have a limited potential for the improvement of traits related to resource efficiency and grain characteristics and we therefore suggest phenotypic selection as the method of choice. By calculating the genotype-by-nitrogen interaction variance of every single genotype, it is possible to identify genotypes deviating from normal behavior. These genotypes can be selected and used as parental components to start a new breeding cycle with the aim of breeding more nitrogen-efficient cultivars. However, our results show that the overall genotype-by-nitrogen interaction variance is rather low, with highest estimates under conventional nitrogen conditions, whereas the highest yielding genotype was always different for every nitrogen fertilization level. From these results we concluded that the selection under conventional nitrogen conditions in early generations followed by trials under the nitrogen condition of the target environment is the best approach to select the highest yielding and nitrogen efficient cultivars for all environments and markets. In conclusion, the breeding of resource efficient and special purpose triticale cultivars is of utmost importance to maintain our yields on a high level and take responsibility for the environment and future generations at the same time. It is a challenging but feasible task. The genetic architecture of these traits is too complex to make successful use of MAS but phenotypic selection methods offer sufficient tools as index selection and multi-stage selection under varying nitrogen fertilization levels, to improve these traits in order to fulfill the task of using the available resources responsibly and at the same time ensuring the supply for a growing world population under more and more extreme climatic conditions.