Genotype by environment interactions and stability for grain yield and other agronomic traits of sorghum in Ethiopia

Abstract

Environmental changes pose major impacts on the performance of genotype with important implications for crop improvement strategies. Hence, breeders pay attention to the effects of GxE interaction (GEI) for exploitation of genetic resources. Twenty sorghum genotypes selected from a large collection of Ethiopian sorghum landraces and two improved varieties were evaluated using a randomized complete block design with three replications at eight locations representing different environmental conditions in Ethiopia. The study aimed at assessing GEI and identifying stable and high-yielding genotypes of sorghum for grain yield and performance for major agronomic traits. Analysis of variance and additive main effect and multiplicative interaction (AMMI) revealed highly significant (P<0.001) variance due to genotypes, environments, and GEI among all traits except for days to maturity. Plant height, days to maturity, panicle width, panicle weight, and grain yield were highly affected by environments and GEI while days to flowering, panicle length, and thousand-grain weight were mainly affected by genotypic variations. The data also indicated the importance of considering GEI in the identification of high-yielding and stable sorghum genotypes across environments. Among testing sites, Chawaka, Gute, and Uke were ideal environments for grain yield and Asosa was the most discriminative environment. Three genotypes (ETSL100808, Merera, and ETSL100474) were superior and stable across test environments for grain yield and related traits. Overall, based on mean grain yield and disease reaction; AMMI, GGE biplot, and regression models, ETSL100808 was the most stable, high-yielding, and disease-tolerant sorghum genotype suggesting its potential both in the breeding program as donors of traits and for direct release as a variety.