Faba bean (Vicia faba L.) is a cool season grain legume whose acreage has constantly declined in traditional producer countries as it has been replaced by more productive cereal crops. However, faba bean is still considered to have great potential as rainfed crop. In order to satisfy the renewed interest in faba bean cultivation yield stability should be improved by exploiting different germplasm types and sowing seasons.In order to understand of genotype by environment interactions and to compare cultivar performance over years and locations a spring faba bean network was established with twenty cultivars grown over three crop seasons at thirteen contrasting locations covering most of Europe. Analysis was performed by heritability-adjusted genotype plus genotype × environment interaction (HA-GGE) biplot analysis. HA-GGE biplot analyses identified that the effect of genotype by environment interaction was higher than the effect of genotypes, allowing identification of three mega-environments, namely Continental, Oceanic, and Mediterranean, in which cultivars performed differently. This supports the need for specific breeding for each specific geoclimatic area. Espresso was the highest yielding cultivar, being also highly stable over the Oceanic and Continental mega-environments. Cultivars Fuego, Hobbit and SR-1060 had also good yield but with a moderate unstability in both Oceanic and Continental mega-environments. Baraca and Alameda yielded poorly at all environments although were the best yielders at Mediterranean locations. Environments as Sumperk and Premesques were identified as the best core test locations for Continental and Oceanic mega-enviroments, respectively, being the locations in which best genotypes could be most easily identified.

Key message We identified marker-trait associations for key faba bean agronomic traits and genomic signatures of selection within a global germplasm collection. Abstract Faba bean (Vicia faba L.) is a high-protein grain legume crop with great potential for sustainable protein production. However, little is known about the genetics underlying trait diversity. In this study, we used 21,345 high-quality SNP markers to genetically characterize 2678 faba bean genotypes. We performed genome-wide association studies of key agronomic traits using a seven-parent-MAGIC population and detected 238 significant marker-trait associations linked to 12 traits of agronomic importance. Sixty-five of these were stable across multiple environments. Using a non-redundant diversity panel of 685 accessions from 52 countries, we identified three subpopulations differentiated by geographical origin and 33 genomic regions subjected to strong diversifying selection between subpopulations. We found that SNP markers associated with the differentiation of northern and southern accessions explained a significant proportion of agronomic trait variance in the seven-parent-MAGIC population, suggesting that some of these traits were targets of selection during breeding. Our findings point to genomic regions associated with important agronomic traits and selection, facilitating faba bean genomics-based breeding.

Partial resistance to powdery mildew in spring barley was evaluated in three plot types: large isolation plots, in 1.4 m z plots in chessboard design with guard plots of spring wheat and in single rows. Percentage leaf area covered by powdery mildew was scored four to six times during the season and partial resistance was characterized by the area under the disease progress curve. Varietal differences were revealed in al three plot designs, differences between the most resistant and susceptible genotypes being of a factor five. Differences between varieties decreased with decreasing plot size. The relationship between single scores of amount of powdery mildew on the upper four leaves and the area under the disease progress curve was high in all plot designs during the first two to three weeks after heading, allowing selection for the trait by one or two scorings. Differential ranking of varieties between different plot designs was observed, and is assumed to be due to increasing plot interference with reduced plot size and reduced distance between plots. A reliable selection for partial resistance could be made in large isolation plots and in 1.4 m 2 plots, but hardly in single rows.Euphytica 35 (1986)

Faba bean (Vicia faba L.) is a high-protein grain legume crop with great potential for further cultivation. However, little is known about the genetics underlying trait diversity. In this study, we use 21,345 high-quality SNP markers to genetically characterise 2,678 faba bean genotypes. We perform genome-wide association studies of key agronomic traits using a Seven-parent-MAGIC population and detect 238 significant marker-trait associations linked to 12 traits of agronomic importance, with 65 of these being stable across multiple environments. Using a non-redundant diversity panel of 685 accessions from 52 countries, we identify 3 subpopulations differentiated by geographical origin and 33 genomic regions subject to strong diversifying selection between subpopulations. We find that SNP markers associated with the differentiation of northern and southern accessions were able to explain a significant proportion of agronomic trait variance in the Seven-parent-MAGIC population, suggesting that some of these traits have played an important role in breeding. Altogether, our findings point to genomic regions associated with important agronomic traits and selection in faba bean, which can be used for breeding purposes.Key MessageWe identified marker-trait associations for key faba bean agronomic traits and genomic signatures of selection within a global germplasm collection.

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