Genotype by Environment Interaction and Yield Stability of Drought Tolerant Mung Bean [Vigna radiata (L.) Wilczek] Genotypes in Ethiopia

Abstract

A multi-environment evaluation of mung bean genotypes was conducted in six environments across Ethiopia to select promising genotypes. This study was conducted to estimate the magnitude of genotypes by environment interaction (GEI) and seed yield stability of the selected drought-tolerant mung bean genotypes across different environments. A total of fifteen mung bean genotypes were used. Out of these, two released varieties were used as standard checks. The field experiments were conducted during the 2019 main cropping season at six locations namely Humbo, Gofa, Melkassa, Konso, Jinka, and Kako using a randomized complete block design with three replications. Data were subjected to analysis of variance, Additive Main Effects and Multiplicative Interaction (AMMI), and GGE bi-plot analysis. A combined analysis of variance revealed significant variations among the genotype, environments, and GEI for yield and yield-related traits, indicating that seed yield was significantly affected by these factors. Analysis of variance from the AMMI model indicated the contribution of environment, genotype, and GEI was 59.6%, 16.8%, and 14.8% of the total variation in seed yield, respectively. Sum squares of the first and the second interaction principal component axis (IPCA) explained 47.4% and 7.4% of the GEI variation, respectively. The IPCA1 mean square was highly significant (P≤0.01) and that of IPCA2 was significant (p≤0.05), indicating the adequacy of the AMMI model with the first two IPCAs for cross-validation of the seed yield variation. The magnitude of the GEI sum squares was 4.4 times that of the genotypes sum squares for seed yield, indicating the presence of substantial differences in genotypic responses across the environments. The results for the AMMI, Yield stability index (YSI), AMMI Stability Value (ASV), and GGE biplot, analyses depicted that the genotypes G6 (NLLP-MGC-24), G13 (Acc006), and G3 (NLLP-MGC-15) were identified as stable and high yielders across the environments and should be considered for variety release. AMMI1 biplot showed Kako was the potential and favorable environment for mung bean production, while Humbo was an unfavorable for mung bean production.