Line × tester analysis in rapeseed: Identification of superior parents and combinations for seed yield and its components

This research was carried out to investigate the genetic structure of the 20 F1s rapeseed hybrids established from five female moderate maturity lines and four early maturity male testers, to determine parents showing general combining ability (GCA) and detect crosses showing specific combining ability (SCA). Significant variance of parents and crosses for all the traits indicated the existence of significant genetic variation among the parents and their F1 cross combinations. Significant variance of parents vs. crosses revealed significant average heterosis for all the traits except first pod height and seeds per pod. High narrow-sense heritability estimates for number of branches and pods length, indicate the importance of additive genetic effects for these traits. Hybrid performance was generally better than parental performance for all the traits except number of branches and also the genetic variation of lines × testers for all the traits were more than lines and testers. Most of the crosses with high mean value of pods per plant were yielded from the parental lines with high mean value of this trait. The crosses including L41×Foma2, Zafar×R42 and L22B×R38 with significant positive SCA effects of seed yield had also high mean values (3400, 3311.3 and 2904.2 kg ha-1 , respectively) of this trait.