Assessment of genetic variability in advanced lines of winter rapeseed

In order to study the genetic variation, identification and selection of superior rapeseed lines in a F4 generation, 20 advanced lines were examined using a randomized complete block design with three replications in the field of Seed and Plant Improvement Institute (SPII), Karaj in 2008-2009. Results of analysis of variance showed that there were significant differences between genotypes for the number of days to initiating and terminating of flowering, number of days to ripening, main stem length, height of first branch from ground surface, main pod length, 1000 seed weight, oil content, seed and oil yield, plant height, number of primary branches, number of pods per branch and per plant. Number of days to beginning of flowering and ripening, 1000 seed weight with 98.27, 92.52 and 91.73 grams had the highest values for broad sense heritability, respectively. The traits like number like of pods per branch and per plant with 23.13 and 16.72 had the highest values for genetic coefficient of variation (GCV). Comparison of mean seed yield showed that the genotypes L1, L9 and Zarfam
with the yield values of 3.49, 3.34 and 3.13 t/ha had the highest performance among the examined genotypes, respectively. Correlation among the measured traits showed that oil yield had a positive and significant correlation with seed yield at 1% of probability level and the traits of oil percent and the secondary pod length showed negative and significant correlation with seed yield at the %10 of probability level. Based on cluster analysis, genotypes were assigned into three distinct groups. One of the resulting clusters consisted of high yielding lines that would besuitable for selection of superior and high yielding rapeseed varieties.