Stability Analysis of Bread Wheat Genotypes by using GGE Biplot Method in Caspian Sea Regions

Wheat (Triticum aestivum) is the largest food crop to cover the earth’s surface in the world. Environmental influences are considered as the measurement criteria for genetic stability.  Sensitivity of a crop genotype to the environmental factors gives rise to genotype - Environment Interaction (GEI). Breeders’ objective is to develop varieties that give high productivity under available environmental conditions.

In this study, stability and adaptation of eighteen promised bread wheat lines along with Morvaread and Gonbad as control cultivars, were evaluated in randomized complete block design with three replications at four regions in Gorgan, Gonbad, Sari and Mogan, during two cropping seasons of 2015-2017.  

Combined analysis of variance indicated significant effects of genotypes and year × location × genotype interactions. Significant interaction effects indicated different reactions of genotypes in various locations. Due to the significant effects of this interaction, genotypes × environment interaction effect was evaluated using GGE Biplot stability analysis. Results of Biplot that revealed mean and stability of genotypes, line11stayed on, in the positive direction of axis had the highest grain yield and line 2 stayed on, in the negative direction of axis had the lowest grain yield. This biplot analysis diagnosed of Mega-environment. In base of this study, among of Gorgan, Gonbad and Sari environments had strong positive correlation and genotypes had the same reactions. Mogan had next to zero correlation with three other locations and reaction of genotypes was independent. The results showed the possibility of selecting stable genotypes with high yield compared to experimental controls, which indicates genetic improvement in bread wheat breeding programs in the northern climate of the country.

Consequently, genotypes 11, 13, 7 and 8 with high grain yield and strong stability were selected.