Assessment Genotype*Environment Interaction in Ten Wheat Cultivars with Regression and Path Coefficient Analysis

This study was conducted to investigate the genotype¬×¬environment interaction effects on yield and yield components of wheat. Ten cultivars of wheat were evaluated in 8 environments (combinations of two levels of nitrogen and four irrigation regimes) in growing season of 2006-2007 at the Research Farm of Isfahan University of Technology. Based on the stability parameters of Eberhart and Russel, Pishtaz and Moghan1 that had higher yield than the average and regression coefficient of 1 (approximately), were more adapted cultivars. However, Khazar and Alvand cultivars showed specific adaptation to better and Falat, Darab and Roshan cultivars to poor environments. Path analysis of genotype¬×¬environment interaction (Tai's method) showed v1 component that indicated the correlation of fertile panicles/m2 with grain yield, was high and significant only for unstable cultivars, therefore, this component is not a suitable criterion for selection of stability. The environmental components showed that fertility and grain filling periods were the most sensitive growth stages of cultivars to the environmental conditions, therefore, it seems that selection for stability based on this component (v2) may not be effective. Genotypic component of v3 (seed weight) was the most effective component of yield stability and based on this component, Pishtaz was the highest yielding and stable cultivar. In general, according to the results of this study, Pishtaz with grain yields of 9.27 t/ha and with the highest stability was determined as the suitable cultivar.