Combining Ability and Heterosis for Seed Yield and Its Components in Indian Mustard (Brassica juncea L.)

Brassica juncea L. is an important oilseed crop which occupies premier position in Indian agriculture. Developing high yielding genotypes has been a major breeding objective in Indian mustard. Present study was conducted at Directorate of Rapeseed-Mustard Research, India, during 2010-2013 to determine General combining ability (GCA) and Specific combining ability (SCA) of parental lines and better parent heterosis of 36 crosses of Indian mustard. Parents and F1 hybrids were evaluated in RCBD with 3 replications. Line×tester analysis involving nine breeding lines and four testers revealed the operation of both additive and non-additive gene actions with predominance of non-additive gene action in controlling yield and contributing traits. Four lines, namely, DRMR 2243, DRMR 2341, DRMR 2486, DRMR 2613, and one tester, NRCHB 101, were adjudged the best general combiner possessing highly significant positive GCA effects for seed yield and yield contributing traits. Significant SCA effects for seed yield, 1000-seed weight, oil content, and other attributing traits in desirable direction were recorded in a series of hybrids and a close association between SCA effects and heterosis was observed amongst the best hybrids identified on the basis of SCA effects. Hybrids DRMR 2243/NRCHB 101, DRMR 2269/NRCHB 101, DRMR 2326/NRCHB 101, DRMR 2341/NRCDR 2, DRMR 2398/NRCHB 101, DRMR 2486/Ashirwad and DRMR 2613/NRCDR 2 exhibited highest magnitude of better parent heterosis with highly significant SCA effects and higher per se performance for seed yield. The high yielding crosses may be exploited for developing superior genotypes and the parents involved may be converted to well adapted cytoplasmic male sterile or restorer lines.