Site regression analysis for interpreting genotype by environment interaction of grain yield in some chickpea (Cicer arietinum L.) genotypes

Multi-environment trials including 3 years and 5 locations for 17 genotypes of chickpea (Cicer arietinum L.) were carried out in Iran to explore the effect of genotype (G) and genotype × environment interaction (GE). The combined analysis of variance indicated that environment (E), G and GE were highly significant (P < 0.01), suggesting differential responses the genotypes. The analysis of variance of grain yield showed that 68.36% of the total sum of squares was attributable to environmental effects, only 9.23% to genotypic effects, and 22.41% to GL interaction effects. Site regression analysis was used to understand the GL interaction pattern. The first 2 principal components were used to create a 2-dimensional GGL biplot and explained 64% and 20% of GGL sum of squares, respectively. The mega-environment analysis identified three chickpea mega-environments in Iran. The first mega-environment contained locations Ghachsaran and Lorestan, where genotype Arman was the winner; the second mega-environment contained locations Ilam and Kermanshah, where genotype FLIP 98-82C and FLIP 98-201C were the winner. The tertiary mega-environment contained locations Gorgan, where genotype FLIP 98-126C was the winner.