Genotype × Environment Interaction for Grain Yield of Some Field pea Genotypes in Central and North Eastern Zones of South Region, Ethiopia

Plant breeders invariably encounter GE interactions when testing varieties across a number of environments. The objective of this study was to identify the stability of grain yield of fifteen field pea genotypes by determining GE interaction effects obtained by AMMI analysis and to select genotypes with better performances depending on the differential genotypic responses to environments. The study was carried out for two consecutive years (2011 - 2012) at three locations and for one year at three additional locations in 2012 (a total of 9 environments) in 5 administrative zones of South Nations, Nationalities and Peoples Region, Ethiopia. The experiment was laid out in randomized complete block design with three replications. To determine the effects of GE interaction on yields, the data were subjected to Additive Main effects and Multiplicative Interaction (AMMI) analysis using GenStat 15thed. The result of combined analysis of variance for grain yield of 15 field pea genotypes tested across 9 environments showed that there is highly significant difference among the environments, genotypes and GE interaction with the contribution of 75.10, 7.95 and 16.94% sum of squares, respectively. The mean grain yield of the genotypes across the environments ranged from 1937.2 kg/ha for genotype G8 to 2755.3 kg/ha for G7, with a grand mean yield of 2248.2 kg/ha. The two best performing genotypes; G15 and G7 with relatively larger absolute IPCA-1 scores were found to have specific adaptations to some environments such as E1 and E7. According to yield stability index (YSI), the most desirable genotypes which can be considered as relatively adapted to wider environments and with grain yield above the grand mean were G4 and G2