Genetic analysis of oil and yield attributing traits in Brassica napus

The present study was conducted to estimate genetic basis of variation, heterosis manifestation and combining ability of various lines for yield attributes and quality traits in Brassica napus L. Six lines named DGL, ZLT-RBJ, B-56, ZMR-2, Long siliqua and ZM-RN were crossed in a 6x6 diallel scheme through controlled pollinations during 2013-14. Parental lines, F1 hybrids, reciprocal crosses and standard check variety Punjab Sarsoon were sown in field during 2014-15 in RCBD with three replications. Data were recorded on different growth and maturity traits including days taken to 50% flowering, days taken to flower completion, days taken to physiological maturity, primary branches/plant, number of siliquae/plant, seeds/siliqua, plant height, seed yield/plant, 1000-seed weight, oil contents and protein contents. The data collected were statistically analyzed for analysis of variance, mean comparison, heterosis manifestation and combining abilities to determine the genetic basis of variation. Results indicated over-dominance type of gene action for all the traits under study except for number of primary branches/plant which was found to be controlled by partial dominance type of gene action. Among parents ZMR-2 and B-56 were found to be good general combiners for most of the traits. F1 hybrids ZLT-RBJ x ZM-RN, ZLT-RBJ x B-56 and Long siliqua x ZM-RN exhibited their superiority for most of the traits studied and were noted as the best specific combiners. DGL carried highest number of dominant genes for days taken to 50% flowering, primary branches/plant, plant height, 1000-seed weight and protein contents. B-56 possessed highest number of dominant genes for days taken to maturity, siliquae/plant and seed yield/plant. ZM-RN had highest number of dominant genes for days taken to flower completion. ZMR-2 had highest number of dominant genes for oil contents and seeds/siliqua. Significant heterosis was manifested for all the traits under study. So these better hybrids can be selected for further improvement on the basis of the results of the present investigations.