GGE Biplot Analysis of Genotype × Environment Interaction in Wheat-Agropyron Disomic Addition Lines

Identification of the genetic architecture of phenotypic stability and management of adaptational genes is a prerequisite for improvement of adaptation. To locate the genes controlling adaptation, disomic addition lines of agropyron (agropyron elongatum, 2n=2x=14) into the genetic background of bread wheat (Triticum aestivum L., 2n=6x=42, cv. ‘Chinese Spring’=CS) were used in a randomized complete block design with three replications under three different conditions (irrigated, pre-anthesis water stress and pos-tanthesis water stress). The GGE [genotype main effect (G) and genotype by environment interaction (GE)] biplot graphical tool was applied to analyze multi-environment trials (MET) data. Combined analysis of variance showed that the environment (E) effect was a predominant source of variation and accounted for 71.93% of the total sum of squares (TSS), while G and GE interaction sources of variation accounted for 5.97% and 22.10% of the total variation, respectively indicating that the GE interaction was more complex. GGE biplot revealed that PC1 and PC2 accounted for 81.98 of the G + GE variation for the grain yield of the genotypes evaluated in 3 environments. According to which-won-where pattern of GGE biplot the vertex genotypes were G1, G3, G4, G5, G7 and G8. These genotypes were the best or the poorest genotypes in some or all of the test environments since they had the longest distance from the origin of the biplot. The G4, G5, well performed in environment E2 (preanthesis stress condition), while the other addition lines showed the lowest performance. Genotype (G2) was more stable as well as high yielding followed by G1 indicating that QTLs controlling yield and stability in agropyron are located on chromosomes 2E and 1E. Comparison of the genotypes with the ideal genotype discriminated addition line G1 (1E) and G2 (E2) as more favorable than all the other genotypes. Negative relationship (obtuse angle) was found between the irrigated (E1), preanthesis water stress (E2) and postanthesis water stress (E3) environments indicating that these environments were different and independent in genotype