Partners and International Organizations
(English)
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AT, BE, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GR, HU, IE, IL, IS, IT, LT, LV, MK, NL, NO, PL, PT, RO, SE, SK, UK
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Abstract
(English)
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The steadily increasing demand of consumers for environmentally sound produced food encourages farmers to switch production towards low input and in particular organic production systems, in Europe and in Switzerland. Besides its good social and political acceptance, low input farming also allows to reduce production costs. However, cereal production under low-input conditions can be biased by large fluctuations between years and between fields in terms of of grain yield and baking quality. Adapted varieties might help stabilise yield and quality performances. The aim of this project is (1) to characterise wheat genotypes adapted and not adapted to low-input agriculture and (2) to elaborate selection criteria that facilitate breeding of wheat varieties for low-input agriculture. The project is composed of two main parts: (1) The evaluation of wheat and triticale genotypes for cultivation under low-input production conditions and (2) the evaluation of bacterial inoculants to stabilise yield and to reduce diseases under low-input conditions. Wheat genotypes have been evaluated in several field experiments. The performance of ancient and modern Swiss winter wheat varieties, representing the past 80 years of Swiss breeding efforts, were compared during 2 years. The field trial was set up with two nitrogen fertilization levels under 'Extenso' conditions (a low-input system in Switzerland) for two years and under organic conditions. Soil coverage in spring, yield, protein yield, yield components and indicators of baking quality were studied. The old varieties outperformed modern varieties in terms of soil coverage in spring. However, this advantage was not significant at the low nitrogen level. The four modern Swiss varieties yielded better, both for grain and for protein. They produced more ears per m2 and more kernels per ear. The Zeleny index, indicating the protein quality, was also superior in the modern varieties. Similar results were found by exclusively considering performance at the lowest of the two fertilizer levels. The old varieties performed as well as the modern varieties under low input conditions only for protein yield and the number of kernels per ear. Further results suggest that old and modern varieties react with yield increase to nitrogen fertilization, but the modern varieties respond better, especially to high fertilizer level. These results illustrate the breeding progress of the last decades and contradict the popular opinion that old cultivars are per se better adapted to low input conditions than modern varieties. The results of this trial under organic conditions largely support the above reported findings. However, the fact that old varieties respond less to high nutrient availability, seems to lead to a higher yield stability which might be preferred by organic farmers. Additional economic analysis has to clarify whether the sacrifice of yield in order to improve yield stability constitutes an economically viable option in organic agriculture. A second field trial is taking advantage of a 40 years ongoing fertilisation trial at Agroscope Changins-Wädenswil with 24 different fertilisation levels ranking from no-fertilisation to high organic and mineral fertilisation. The performance of 11 modern European wheat varieties was tested for yield, protein yielding and nutrient uptake efficiency during the growing seasons 2006 and 2007. This trial allows to study the specific interactions between the genotype and its environment (GxE interaction) under marginal soil fertility conditions. Results show an interaction between varieties and soil fertility level and an interaction between varieties and nitrogen fertilisation in terms of grain yield. This observation is supported by analyses of the nitrogen use efficiency of the varieties. These findings support our hypothesis that there are genetic differences between varieties. We have evidenced modern wheat varieties, that are well adapted to low-input agriculture and we have developed novel methods and approaches for this. A third series of field trials is performed in the frame of a COST 860 ringtest. Here 15 modern European winter wheat varieties with high baking quality were tested in 5 European countries under 15 different environmental conditions. The trial sites represented low-input and organic growing conditions and differed in pedo-climatic conditions and fertilisation levels. The goal was to detect germplasm that is particularly adapted to low input and organic conditions. These varieties could be directly recommended to farmers and may be used further for breeding purposes. The trial at ACW has been conducted at three different nitrogen fertilization levels and was complemented with additional varieties. The results show that a variety that performs well under high nitrogen levels is not necessarily superiour to other varieties under low nitrogen or under organic conditions. This proves our hypothesis on the presence of specific genetic factors for nutrient efficency under low nutrient conditions. It is yet unknown which genetic factors are involved therein. The second part of this project concerns the contribution of beneficial microbes on the performance and health of wheat. This part is linked with the SER Projects of M. Maurhofer (ETHZ), C. Keel (UNIL) and P. Mäder (FibL). The interactions of four strains of Pseudomonas fluorescens and three wheat cultivars (Zinal, Arina, Cimetta) were studied for their ability to colonise the rhizospere of wheat and to control the leaf disease brown rust (Puccinia triticina) as well as the seed borne disease common bunt (Tilletia caries). The disease level, the root colonisation by the inoculum as well as the chlorophyll activity, an indicator of physiological activity, have been recorded. Presence of bacteria increased the clorophyll activity in the greenhouse but not in field trials. Leaf rust reduction was more pronounced in the variety Zinal, a moderately resistant variety, than in Arina which is a very susceptible variety. In all combinations, the presence of beneficial bacteria on the root reduced the disease severity by a factor of three to five depending on the applied strain. Similarly, the co-inoculation of seeds with Pseudomonas fluorescence and common bunt showed a reduction of infection in the same way in all combinations. Under field conditions, infections by common bunt were not significanly reduced by the co-inoculation with pseudomonads. Taken together, our findings demonstrate that root-associated pseudomonads modulate the resistance response of wheat against leaf rust and common bunt. In presence of Pseudomonas spp., the plant response depended on the genotype of both the microbes and the wheat varieties, suggesting a straight interaction at the molecular level. This is further supported by the observation that the reduction of disease on the leaf is correlated with the degree of bacterial colonisation on the roots. All these results are very promising for the selection of beneficial bacteria-wheat interactions intended for organic cropping systems. The specific interaction of bacteria and wheat genotypes has been evidenced here. The success of the activity of the inoculum depends on its interaction with the host. These findings offer a new trace of investigation for breeders and pathologists to increase the efficacy of biological disease control strategies. In this project, it was possible to improve existing breeding strategies and to develop new ones for the obtention of new wheat and other cereal varieties adapted to low input conditions. These new breeding tools include selection tools as well as methods to study receptiveness of wheat varieties for the colonisation of beneficial pseudomonads.
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