Genotype x environment interaction and yeild stability of soybean [glycine max (l.) merrill] genotypes in western Ethiopia

Abstract

Soybean (Glycine max (L.) Merrill) is one of the most important oil crops globally. It is recently introduced crop in Ethiopia and currently getting important position among oil crops. However, production is affected by several factors. Lack of stable genotypes across the soybean production area is one of the problems. Thirty soybean genotypes were planted in alpha lattice design with three replications at six soybean major growing agro-ecologies of Western Ethiopia (Jimma, Mettu, Teppi, Bako, Assosa and Pawe) in 2020 cropping season. With the objectives of determining the effects of GEI, on yield of new soybean genetics and identifying better performing and well adapted soybean genotypes than the local varieties, and to prepare for registration and release of selected high yielding varieties in the different soybean agro-environment conditions of western Ethiopia. The eleven traits subjected to the combined analysis of variance showed a highly significant (p<0.01) effect of genotype, location, and genotype x location interactions (GLI). Similarly the combined AMMI ANOVA for grain yield revealed that there were highly significant differences among genotypes, locations and genotype by location interactions and accounted 11.3%, 41.8% and 25.2% of the total variations respectively. The highest percentages of environmental variations are an indication that environment is the major factor that influences the yield performance of soybean grain in Ethiopia. In addition, the first two IPCAs were significant and accounted for 69% of the total interactions sum squares. Eight stability measures viz; Wricke’s Ecovalence (Wi), Shukla’s stability variance(σ2), Lin and Binns Cultivar Superiority Measure(Pi), Eberhart and Russell analysis (bi and S2di), Additive Main Effect and Multiplicative Interaction (AMMI) model, AMMI Stability Value (ASV),Yield Stability Index (YSI),Genotype Main Effect and Genotype by Environment Interaction Effect (GGE) bi plot analysis Model were used to evaluate the stable genotypes across the testing locations. Genotypes TGX2014-16FM and TGX2002-3DM were more stable by Wricke’s Ecovalence Analysis, and Shukla’s Stability Variance. Genotypes S1150/5/22 and TGX2001-8DM were more stable by Eberhart and Russell analysis. Genotypes ScStatus and S1079/6/7 were more stable by Cultivar Superiority Measure. Genotypes S1150/5/22 and ScStatus were more stable by Yield Stability Index. Genotypes S1150/5/22 and TGX2014-16FM were more stable by AMMI Stability Value. Genotypes ScStatus and Pawe-3 were selected as better genotypes that appeared in the four locations by AMMI analysis. According to one year data, the six locations are grouped into three mega environments for soybean production with different winning genotypes and genotype ScStatus was an ideal genotype, while location Pawe was an ideal environment by GGE analysis. Genotypes ScStatus and S1079/6/7 are the two of the best performing genotypes than the other genotypes and control varieties (Pawe-2 and Pawe-3) in grain yield across locations. Therefore, those the two highest yielder genotypes have a potential to be registered in Ethiopia. However, this trail need to be repeated for one more season, and or two of the best performing genotypes will be verified along with the checks on farmers' fields for release.