Estimation of Genetic Parameters for Yield, Yield Components and Glucosinolate in Rapeseed (Brassica napus L.)

Eight genotypes of rapeseed (Brassica napus L.), including six cultivars and two breeding lines, were used to determine the genetic parameters for number of pods per main axis (NPM), number of pods per plant (NPP), length of pod (LOP), number of seeds per pods (NSP), 1000-seed weight , seed yield, and total glucosinolate. Analysis of variance based on Hayman’s method revealed significant general (a) and specific (b) combining ability mean squares for all traits except for 1000-seed weight, which indicated the importance of additive and non-additive genetic effects. For 1000-seed weight, only the general combining ability mean square was statistically significant. Significant ratios of a to b mean squares and high narrow-sense heritability estimates were observed for 1000-seed weight and total glucosinolate, which indicated the importance of additive genetic effects for these traits. Therefore, the efficiency of selection for improving these traits will be high. The significant b1 (mean deviation of F1’s from their mid-parental values) meansquares for all of the studied traits except LOP and 1000-seed weight, exhibited directional dominance and subsequently significant average heterosis. Significant maternal (c) mean squares were observed for all of traits, except LOP. Among yield components, NPM and NPP had a significant correlation with seed yield and can therefore be used as good criteria for improving seed yield. The correlation between seed yield and total glucosinolate was not significant, and so reducing this antiquality trait without any considerable changes in seed yield is possible. In general, the parents PF7045/91 and BL1 were good combiners and the crosses BL1×PF7045/91, BL1×BL2 and PF7045/91×Shiralee were good combinations for improving seed yield and total glucosinolate, simultaneously