pattern analysis of genotype × field environments interaction for grain yield in wheat using ammi method

this research was conducted to investigate genotyp×environment interaction for grain yield of ten wheat cultivars in 8 environments (combinations of two nitrogen fertilizer treatment and four irrigation regimes). analysis of additive main effects (analysis of variance) and multiplicative interaction effects (principal component analysis) revealed that the effects of genotype, environment and genotype ×environment interaction were highly significant. three first principal components explained 89% of the interaction sum squares. biplot of the first principal component and mean grain yields for genotypes and environments revealed that high yielding genotypes of pishtaz and moghan1 were more stable cultivars. pattern analysis of two first significant principal components for genotypes and environments and also cluster analysis based on stability statistics of ammi3 model (sipc3 and ev3) showed that pishtaz genotype had general stability. the grain yield of this cultivar was higher than the average of all genotypes, it was implied that this cultivar had general adaptability. khazar cultivar was ranked as the second stable cultivar with having grain yield of approximately as much as the average of all genotypes; thus it was considered as a genotype with moderate general adaptability. cultivars of alvand, sabalan, moghan1, darab and falat showed very low stability. sardary and omid with lower yield were recognized as unstable cultivars. also, it was found that all environments had contribution in the interaction effects.