Stability Analysis of Oil Yield in Different Oilseed Rape (Brassica napus L.) Genotypes in Two normal and Delayed Sowing Date in Kermanshah Province

In order to evaluate oil yield stability in oilseed rape genotypes and genotypeenvironment interaction, 22 oilseed rape genotypes were evaluated using RCBD design with 4 replications in Agricultural Research Station of Islam Abad-e-Gharb during 3 cropping seasons in normal and delayed sowing date conditions. Combined variance analysis showed that genotype, environment and genotypeenvironment interaction were statistically significant. Proportion of environment effect followed by genotypeenvironment interaction was so greater than genotype effect. Based on biplot of two first genotypeenvironment interaction components, that explains proportion of oilseed rape genotypes in genotypeenvironment, genotypes Parade, Kristinia, Goliath, Shiralee, Kimberly and Elect were located next to center of biplot so that had the least proportion for the GenotypeEnvironment effect and were stable from the viewpoint of oil production. AMMI stability values (ASV) of genotypes confirmed the above mentioned results. Hyola401 and Zarfam were located away from the center of biplot so that were unstable genotypes for oil production. Biplot display indicated that environments E1, E3 and E4 had the most scores for genotypeenvironment interaction whereas E2 had the least proportion in genotypeenvironment interaction effect. Dissimilarity in ranking of selected genotypes from the viewpoint of oil yield based on other stability parameters suggests that it would be better using of numerous stability parameters to reliable and accurate selection of stable genotypes.