Heterosis and Combining Ability in Rape Seed (Brassica rapa L.)

Field experiment on rapeseed (Brassica rapa L.) involving 7x7 half diallel cross excluding reciprocal were done at the Sher-e-Bangla Agricultural University, Dhaka during the winter season of 2006-2007 to estimate their Heterosis and Combining ability. Out of 21 crosses C2, C5, C7 and C14 showed highly significant heterosis over both mid and better parent for seed yield per plant. The hybrid C11, C5, C10, C6, C21 showed significant heterosis for other yield contributing characters. The variance due to GCA and SCA were highly significant for all the characters except hundred seed weight and seed yield per plant. Highly significant GCA effect was found in case of hundred seed weight where highly significant SCA effect was found for seed yield per plant. The parent BARIsar-9 was an excellent general combiner for earliness and dwarfness where as Tori 7 for earliness, siliquae per plant and length of siliqua; BINAsar-6 and Shafal for primary branches per plant; BINAsar-6 for hundred seed weight and Agroni for more seeds per siliqua. The SCA estimates indicated that the cross C7 for early flowering, early maturity and seed yield per plant.