Stability Analysis of Rapeseed Genotypes Targeted Across Irrigated Conditions of Pakistan

This study was conducted to determine the performance of rapeseed genotypes under irrigated conditions, analyze their stability, and identify superior genotypes that could be valuable for rapeseed improvement or varietal release. Eleven advanced breeding lines/ cultivars including two checks were tested for a period of 2 year (2010-11 and 2011-12) using a randomized complete block design with 4 replications at seven different locations across Pakistan. The genotype x environment was analyzed using linear regression technique. The analysis of variance for seed yield showed that genotypes, locations and their interaction all were highly significant, combined analysis of variance for seed yield stability was estimated by using the Eberhart and Russell method which revealed significant differences for seed yield among genotypes and environments. The regression coefficient (bi) of eleven genotypes ranged from 0.56 to 1.27. Out of 11 genotypes RBN-04722 is categorized as the most stable genotypes over the locations under study because of its above average yield responses and regression coefficient (bi) near to 1.0, non significant S 2di) and high value of R2i(81%). The genotypes SPS-N-7/28 and Gold Star having regression coefficient significantly greater than unity (bi > 1.0) indicated that these genotypes are suitable for favorable environments only. In contrast the genotypes AUP-06-10, 04-k12/13-10-1 and AUP-04-10 had regression coefficient significantly less than unity (bi < 1.0) indicating that these genotypes are suitable for poor environments.