Seed Yield Stability and Genotype × Environment Interaction in Common Bean (Phaseolus vulgaris L.) Varieties in Dawro Zone, Southwestern Ethiopia

Stable yield performance of genotypes is very important in countries like Ethiopia where means to modify environments are limited. However, happening of significant genotype X environment interaction (GEI ) complicates selection of stable genotypes. In Ethiopia, the yield potential of common bean varieties is underutilized due to inadequate addressing of all potential areas and mismatch between selection and production environments. Thus, 14  common bean varieties were evaluated at seven locations for seed yield performance using Randomized complete block design with three replications in the 2010 main cropping season to estimate the magnitude of GLI effects and to identify broadly or specifically adapted varieties. Combined ANOVA, AMMI and GGE biplot models were used to analyze the data. Both main and interaction effects were highly significant (P<0.01) and location, variety, and GLI explained 50.3%, 28.8% and 20.9% variations, respectively, indicating greater influence of location and importance of simultaneous consideration of mean performance and GLI (stability). PC1 and PC2 were highly significant (p < 0.01) and together contributed more than 79% variation in the GLI sum of squares. AMMI 1 biplot enabled identification of both high seed yielding and broadly adapted Varieties, Zebra-90, Goberasha, Roba-1, Nasir, and Omo-95. GGE biplot analysis suggested presence of two mega-locations and enabled identification of specifically adapted varieties. However, GLI couldn't be exploited from one season experiment and, therefore,  farmers in the Zone should grow high seed yielding and broadly adapted varieties.