Studies on combining ability and heterosis in rice (Oryza sativa L.)

Abstract

Combining ability analysis was carried out in rice involving seven lines, four testers and 28 cross combinations. The combining ability variances revealed that SCA was greater than GCA indicating the preponderance of non-additive gene action for all the traits viz., days to 50 per cent flowering, plant height, number of productive tillers per plant, panicle length, number of grains per panicle, hundred grain weight, grain yield per plant, kernel length, kernel breadth and kernel L/B ratio. From standard heterosis, hybrids viz., STBN 4/ADT 45, STBN 3/ADT 45 and ADT 43/PMK 3 recorded significant standard heterosis for most of the traits. Among the parents ADT 43, STBN 3, STBN 4 among lines and ADT 45 among testers were good general combiners for grain yield per plant and other component traits. Among hybrids, STBN 3 x ATD 45, STBN 4 x ADT 45 and ADT 43 x PY 3 recorded significant and positive sca effects for grain yield per plant which indicated the involvement of additive type of epistasis for grain yield and other characters.