Seed Yield and Its Related Traits Performance of Common Bean (Phaseolus vulgaris L.) Varieties in Dawro Zone, Southwest Ethiopia

Poor addressing of all potential areas and slow turnover of old cultivars for more than 15-30 years are serious bottlenecks limiting production and productivity of common bean in Ethiopia. Farmers in the study area, Dawro zone, had been cultivating common bean landraces for about five centuries and Red wolaita for about 30 years. Red wolaita is low seed yielding and poor in quality due to loss of its genetic identity because of mixing up with landraces, genetic drift, and natural out crossing. Hence, thirteen newly released common bean varieties reported for their higher seed yield potential and Red wolaita were evaluated at seven locations for seed yield and its related traits performance using RCBD design with three replications in Dawro zone, southwest Ethiopia, in the 2010 main cropping season to select higher seed yielding and broadly adapted varieties. Analysis of variance (ANOVA) and additive main effects and multiplicative interaction (AMMI) models were used to analyze the data. The analysis of variance revealed presence of highly significantly difference (P < 0.01) between varieties for seed yield and its related traits performance. Combined AMMI model analysis of variance partitioned the variability in seed yield performance of varieties with the largest effect of location (50.27%) followed by variety effect (28.81%) and then variety by location interaction (GLI) effect (20.92%) indicating highly significant complication of GLI in selecting high seed yielding and broadly adapted varieties with greater influence of location. AMMI 1 biplot analysis enabled identification of higher seed yielding and broadly adapted varieties, Zebra-90, GobeRasha, Roba-1, Nasir, and Omo-95. Higher seed yielding varieties were earlier to flower, but latest to mature. Longer plant height, and higher number of primary branches per plant, pods per plant, and seeds per pod had better contributed to higher seed yield performance. Generally, since broadly adapted varieties were the winners with rank change within themselves at all locations and no variety had performed specifically well, Zebra-90, GobeRasha, Roba-1, Nasir, and Omo-95 were recommended for production in the Zone and now Nasir, which has similar seed color with the old and low seed yielding cultivar in the Zone, Red wolaita, has got wider acceptance and at popular production in the Zone. Keywords: AMMI, Broad adaptation, Dawro Zone, GLI, Seed yield, Variety, Yield related trait