Genotype by Environment Interaction for Grain Yield and Association among Stability Parameters in Bread Wheat (<i>Triticum aestivum</i> L.)

Abstract

Bread wheat ( Triticum aestivum L.) is most important cereal crop in Ethiopia. Lack of genotypes with wide stability across environments has been one of the most important constraints of wheat production in the country. Field experiments were conducted in Halaba and Bule, South Ethiopia, in 2016 and 2017, in order to estimate grain yield stability and association among stability parameters. Fifteen improved bread wheat genotypes were grown under randomized complete block design with three replications. Mean yield for Halaba 2016, Halaba 2017, Bule 2016 and Bule 2017 was 3.83, 1.89, 2.90 and 3.59 tons/ha, respectively. Genotypes Lemu (3.25 tons/ha) and Mandoyu (3.18 tons/ha) had high mean yield, and low values of environmental variance (S 2 i), coefficient of variation (CVi), stability variance (δ 2 i), ecovalence (Wi) and deviation from regression (S 2 di). Genotypes Biqa (3.69 tons/ha) and Shorima (3.66 tons/ha) had high mean yield, coefficient of regression (bi) and coefficient of determination (R 2 i ≥ 0.94) as well as low values of δ 2 i, Wi and S 2 di. Grain yield had positive rank correlation with bi (r = 0.75, p < 0.01), R 2 i (r = 0.70, p < 0.01) and rank sum (r = 0.82, p < 0.01). Rank correlation among δ 2 i, Wi and S 2 di was high (r ≥ 0.98, p < 0.01). Present study showed that genotypes Lemu , Mandoyu and Hidase, and Biqa and Shorima would be recommended for wide adaption, and for more favorable environments, respectively. It could also be suggested that one of Wi, δ 2 i, S 2 di and rank sum would be used for ranking of genotypes.