Das Ertragsniveau von Composite Cross Winterweizenpopulationen mit unterschiedlichen Managementhistorien in zwei Bodenbearbeitungssystemen

Die Züchtung heterogener Composite Cross Populationen (CCPs) und ihre darauffolgende Anpassung an lokal vorherrschende biotische und abiotische Stressfaktoren hat zum Ziel, die Ertragsstabilität und Resilienz des Weizens zu steigern. Die Ertragsleistung von sechs CCPs mit identischem genetischen Hintergrund aber unterschiedlichen Managementhistorien wurde in einem Langzeitversuch mit verschiedenen Bodenbearbeitungs- und Düngungssystemen getestet. Diejenigen CCPs, die seit 2005 konventionell angebaut wurden, erzielten einen signifikant höheren Ertrag unter Pflug- als unter Minimalbodenbearbeitung. Für die seit 2005 ökologisch angebauten CCPs konnte kein signifikanter Ertragsunterschied zwischen den Bearbeitungssystemen festgestellt werden. Die seit 2008 in einem Breitsaatverfahren ohne Unkrautkontrolle angebauten ökologischen CCPs waren sogar tendenziell ertragsstärker unter Minimalbodenbearbeitung. Daraus ergibt sich, dass die jeweiligen Selektionskräfte, die durch langfristiges Management auf die CCPs eingewirkt haben, zu einer unterschiedlichen Anpassung an spezifischen Umweltbedingungen geführt haben

Anpassungsprozesse in der Frühentwicklung von Weizenpopulationen über 11 Generationen an das Anbausystem

Eine wichtige Anpassung an den ökologischen Anbau ist eine zügige Frühentwicklung und ein Wurzelsystem, das an organische Düngung angepasst ist. Eine Halbdiallelkreuzung aus insgesamt 20 europäischen Winterweizensorten wurde 2001 hergestellt und insgesamt drei Subpopulationen aus neun Hochertragseltern (CY), eine mit 12 Backqualitätseltern (CQ) und eine aus allen Eltern (CYQ) zusammengestellt. Seit der F5 wird Saatgut unter konventionellen und ökologischen Anbaubedingungen in jeweils zwei parallelen Populationen getrennt nachgebaut. Saat jeder Generation wird bei -20o C aufbewahrt. Für die Versuche wurden Generationen F6, F10, F11, F15 in einem Feld zu F6.1, F10.1, F11.1, F15.1 vermehrt. Frisches Saatgut wurde im Hydrokultursystem zwei Wochen bei 18/12 oC (Tag/Nacht) angebaut und die Wurzel- und Sproßlängen und Gewichte gemessen. Von der F6.1 zur F15.1 verlängerten sich die Seminalwurzeln unter ökologischen aber nicht unter konventionellen Bedingungen signifikant. Eine Ausnahme stellt die F11.1 Generation dar, die in der F11 extremem Kahlfrost durchlitten hatte und unter beiden Anbaubedingungen deutlich kürzere Wurzeln produzierte als ein Jahr zuvor oder vier Jahre später. Die Seminalwurzellänge in den konventionell angebauten Y CCPs signifikant kürzer als in den ökologisch angebauten. Im Gegensatz dazu unterschieden sich die Q Populationen nicht, während sich die YQ Populationen unter ökologischen Bedingungen wie die Q CCPs verhielten, unter konventionellen Bedingungen aber eine Zwischenposition zwischen Y und Q einnahmen. Insgesamt nahmen die Sproßlängen in allen Populationen leicht zu in den ersten vier Generationen und blieben danach gleich. Die CCPs zeigen auch nach 15 Generationen konsistent ihre ursprünglichen genetischen Unterschiede. Der Nachbau in großen Parzellen kann die genetische Breite der CCPs auch durch einmaligen Extremereignisse grundsätzlich erhalten

Heterogeneous Winter Wheat Populations Differ in Yield Stability Depending on their Genetic Background and Management System

Twelve winter wheat composite cross populations (CCPs), based on three genetic backgrounds and maintained at the University of Kassel, Germany, under both organic and conventional management, were assessed for yield performance and stability in comparison to two commercial varieties over eight and 10 experimental years. A number of stability parameters were chosen in order to identify populations with either adaptation to specific environments or broad adaptation across environments. The genetic effects of the CCP parental varieties were clearly present when comparing CCP yield performance in both management systems. Compared to the variety ‘Capo’, CCPs yielded similarly under organic, but poorer under conventional conditions. Under both management systems, CCPs with the broadest or with a more modern (high yielding) genetic base achieved the greatest yield stability, exceeding that of ‘Capo’, and demonstrating the buffering capacity of genetic diversity. CCPs with a genetic background of high yielding parents reacted most strongly to the different environments and apparently diverged under conventional management over time. Possibilities to improve CCPs through the addition of new genetic material while maintaining the benefits of diversity to achieve higher and more stable yields, particularly in light of increasingly unpredictable climatic conditions are discussed

Supply Chain Perspectives on Breeding for Legume–Cereal Intercrops

Compared to sole crops, intercropping—especially of legumes and cereals—has great potential to improve crop yield and resource use efficiency, and can provide many other ecosystem services. However, the beneficial effects of intercrops are often greatly dependent on the end use as well as the specific species and genotypes being co-cultivated. In addition, intercropping imposes added complexity at different levels of the supply chain. While the need for developing crop genotypes for intercropping has long been recognized, most cultivars on the market are optimized for sole cropping and may not necessarily perform well in intercrops. This paper aims to place breeding targets for intercrop-adapted genotypes in a supply chain perspective. Three case studies of legumes and cereals intercropped for human consumption are used to identify desirable intercrop traits for actors across the supply chains, many of which are not targeted by traditional breeding for sole crops, including certain seed attributes, and some of which do not fit traditional breeding schemes, such as breeding for synchronized maturity and species synergies. Incorporating these traits into intercrop breeding could significantly reduce complexity along the supply chain. It is concluded that the widespread adoption and integration of intercrops will only be successful through the inclusion and collaboration of all supply chain actors, the application of breeding approaches that take into account the complexity of intercrop supply chains, and the implementation of diversification strategies in every process from field to fork

Supply Chain Perspectives on Breeding for Legume–Cereal Intercrops

Compared to sole crops, intercropping—especially of legumes and cereals—has great potential to improve crop yield and resource use efficiency, and can provide many other ecosystem services. However, the beneficial effects of intercrops are often greatly dependent on the end use as well as the specific species and genotypes being co-cultivated. In addition, intercropping imposes added complexity at different levels of the supply chain. While the need for developing crop genotypes for intercropping has long been recognized, most cultivars on the market are optimized for sole cropping and may not necessarily perform well in intercrops. This paper aims to place breeding targets for intercrop-adapted genotypes in a supply chain perspective. Three case studies of legumes and cereals intercropped for human consumption are used to identify desirable intercrop traits for actors across the supply chains, many of which are not targeted by traditional breeding for sole crops, including certain seed attributes, and some of which do not fit traditional breeding schemes, such as breeding for synchronized maturity and species synergies. Incorporating these traits into intercrop breeding could significantly reduce complexity along the supply chain. It is concluded that the widespread adoption and integration of intercrops will only be successful through the inclusion and collaboration of all supply chain actors, the application of breeding approaches that take into account the complexity of intercrop supply chains, and the implementation of diversification strategies in every process from field to fork

High Buffering Potential of Winter Wheat Composite Cross Populations to Rapidly Changing Environmental Conditions

A winter wheat composite cross population (CCP), created in the UK in 2001, has been grown in Germany, Hungary, and the UK since 2005 (F5 generation). In 2008/09 (F8), a cycling pattern for the populations was developed between partners to test the effects of rapidly changing environments on agronomic performance and morphological characteristics. One CCP was grown by eight partners for one year and subsequently sent to the next partner, creating “cycling CCPs” with different histories. In 2013, all eight cycling CCPs and the three non-cycling CCPs (from Germany, Hungary, and the UK) were included in a two-year experiment in Germany with three line varieties as references. Differing seed weights of the F13 at sowing affected some agronomic parameters under drought conditions in 2014/15 but not under less stressful conditions in 2013/14. In both experimental years, the CCPs were comparable to the line varieties in terms of agronomic performance, with some CCPs yielding more than the varieties under the drought conditions of 2015. The results highlight the potential of CCPs to compete with line varieties, while the overall similarity of the CCPs based on their origin and cycling history for agronomic traits indicates a high buffering potential under highly variable environmental conditions