Abstract
Heterosis and combining ability effects were assessed in an 11-parent diallel cross involving 8 scented and 3 non-scented rice (Oryza sativa L.) stocks. Heterosis was significant for grain yield and its component characters in most of the hybrids. Maximum heterosis for grain yield per plant was obtained in the cross between Karnal Local, a high quality scented rice and a semi-dwarf scented parent Dawag. The estimates of general combining ability (GCA) and specific combining ability (SCA) indicated predominance of non-additive gene effects for days to flower, plant height, panicle length, tillers per plant, number of fertile tillers per plant, grain yield per plant, 1000-grain weight, and length to breadth (L:B) ratio. Cultivar Karnal Local showed good GCA for panicle length, tillers per plant, number of fertile tillers per plant, grain yield per plant, and grain L:B ratio. Bindli semi-dwarf mutant Dawag and Basmati 372 showed good GCA for earliness and dwarfing. The present study suggested that a greater number of favourable genes can be combined in one genotype to obtain maximum yield without loss in quality characteristics from crosses involving good combining scented parents like Karnal Local, Basmati 1, Basmati 372 selection, and Bindli semi-dwarf mutant. The crosses involving these parents will prove extremely useful in generating high-yielding dwarf aromatic rices through careful selection for quality traits, yield, and resistance to bacterial leaf blight and white backed plant hopper.
