COMBINING ABILTY AND HETEROSIS THROUGH LINE X TESTER ANALYSIS IN Brassica napus L.

Abstract

The study was conducted to evaluate six female parents (CMS lines) and 3 male parents (testers) in a line x tester mating design at the research field of Sher-e-Bangla Agricultural University, Dhaka, during November 2009 to March 2010 to estimate their combining and heterosis. The data recorded on 18 F1 s and their parents for their combining ability indicated that (ICA effect was significant for days to fifty percent flowering, plant height, No. of siliqua per plant, seed per siliqua, primary branch & secondary branch per plant and seed yield per plant . The specific combining ability (SCA) effect was significant for all the characters. High ratio of SCA and GCA variance was observed, indicating preponderance of non additive gene effects in the inheritance of the yield and yield relating characters under study. Among the lines, CMS2, CMS3 and CMS5 were found as good general combiners. But seven hybrids exhibited good specific combiner among eighteen hybrids. Different types heterosis i.e. heterosis over mid parent (Hm), heterosis over better parent (Rb) and heterosis over standard check (HC) were estimated to evaluate eighteen hybrids for seed yield and yield related characters, where BARI Sharisha-7 was taken as check. The average heterosis for seed yield of eighteen hybrids over mid parent was 19.26% and that of better parent and standard check was 7.96% and 73.90%, respectively. Sixteen hybrids out of eighteen showed higher plant height than the standard check variety.