Stability Analysis of Durum Wheat Genotypes by GGE Biplot Method

Nineteen durum wheat lines selected from preliminary yield trial along with Dehdasht as a control cultivar, were evaluated in a randomized complete block design with three replications at five regions in Iran including Gachsaran, Gonbad, Khoramabad, Moghan and Ilam during three cropping seasons of 2012-2015. Combined analysis of variance indicated significant effects of year, location, genotype and year × location, year × genptype and year × location × genotype interactions on durum wheat grain yield. Screet test indicated the first foure principal components had high contribution of geenotype × environmentinteractions (GEI), so that the PC1 and PC2 was explained 22.0% and 18.71% of GEI variation. Mosaic plot revealed that 11.54% of total variation is illustrated by genotype and 88.46% by GEI effects. Heatmap plot was also indicated G16, G19 and G20 had high grain yield in many of environments. The polygon view of biplot indicated G8, G7, G20 and G13 were as stable genotypes to the tested environments according to the closest distance to biplot origin, while  G18, G15 and G11 was not adaptable to any of environments. The simultaneous studying of the effects of genotype (G) and genotype-environment interactions (G×E) by average tester coordinate (ATC) view of biplot illustrated that G2, G7, G1 and G20, in addition to high grain yield, are also more stable to the tested environments than the other genotypes, and can be proposed as stable genotypes. G1 and G2 are placed close to the ideal genotype, are most desirable than the other genotypes. The vector view of GGE biplot indicated discriminating and representative environments (E5 and E3) are good environments for selecting generally adapted genotypes. Consequently, G7, G8, G20 and G13 with strong stability and high grain yield can be used in selection/ recommendation process of cultivar.