Combining ability and heritability in rice

A diallel analysis of combining ability for five characters in six varieties of rice (Oryza sativa L.) revealed that general and specific combining ability variances were significant for all the characters except 100 grain weight. BJ 1 was good general combiner for yield per plant, grains per panicle and for panicle number. Wase Aikoku-3 and M. Sungsong were good general combiners for panicle length and grains per panicle respectively. The crosses with high specific combining ability generally involved high × low combinations.

The higher magnitude of analytical estimates due to s.c.a. (σ_s^‸2) than g.c.a. (σ_s^‸2) and high degree of dominance with low Rg values for all characters except panicle number indicated the presence of non-additive gene action for all the characters except panicle number. The additive genetic variance was more important for panicle number. The narrow sense heritability estimates was of higher magnitude for panicle number than for other characters.