Investigation of Genotype × Environment Interaction for the Stability of Safflower Seed Yield through the GGE Biplot Analysis

Safflower is an important drought and salt tolerant plant adapted to the climate conditions of Iran. Multi-environment trials play an important role in crop breeding programs to identify genotypes with high and stable yield. In the present study, yield stability of 17 safflower genotypes were tested under the rainfed condition in a three years trials based on randomized complete block design with 3 replications at Gachsaran Agricultural Research Station during 2004-2006 cropping seasons. The results of the combined analysis of variance showed that main effects of genotype and environment on the stability of Safflower Seed Yield were significant at 1%, and GEI was significant at 5% probability level. The results of analysis of variance showed that 45.2% of total variation was due to environment while 26.0% of variation was belonged to genotype and G×E interaction. GGE (G plus GE) biplot model was used to evaluate seed yield stability in safflower genotypes. The first two principle components (PC1 and PC2) together explained 94.2% of the total variability, therefore most of the information could be graphically displayed in the PC1 vs. PC2 biplot. The biplot of comparison of the safflower genotypes with the ideal genotype revealed that Sina, Syrian, Cyprus Bergon and Cw-4440 were the closest genotypes to the ideal cultivar, and Esfahan, Cw-74 and Hartman had the most distance from the ideal cultivar.