Heterosis and combining ability in rapeseed (Brassica napus. L)

The study was initiated to evaluate 15 female parents (lines) and 3 male parents (testers) in a line × tester mating design. The data recorded on 45 F1¢s and their parents for their combining ability indicated that gca variance component was significant for all the characters. The specific combining ability component of variance was significant for all the characters showing predominance of non-additive component for all the characters except days to maturity and plant height. Among the lines, TKG-G-16, GSC-865-2 and HNS 9601 were superior combiners for seed yield. TKG-G-6×GSL-1, GSC-865-2×GSL-1 and HNS-004× GSL-1 were crosses which showed significant sca and heterotic effects for seed yield. The maximum heterosis manifested for seed yield, where as TKG-865-2 × GSL-1 gave 74% heterosis over the better parent GSL-1. The study also hinted upon use of average and good combiners for the development of F₁ hybrids in Brassica napus which has now been feasilble with the stabilization of CMS systems in this crop.