Heterosis and combining ability studies for yield components in rice

Studies on heterosis and combining ability were conducted with 21 F(1)s generated from seven parents crossed in diallel fashion. The results revealed that the estimates of heterosis and heterobeltiosis were variable among crosses in desirable direction. The gca/sca variance indicated that all the characters were predominantly governed by nonadditive gene action except for days to 50% flowering, panicle length and 1000-grain weight. The parents identified as good general combiners were MTU 1010, JGL 13595 and NLR 34449 for early flowering, JGL 3844 and MTU 1081 for short stature and MTU 1075 for more number of tillers and panicles, panicle length and grain yield per plant. The best specific cross combinations identified in the present investigation were MTU 1010/JGL 13595 (earliness), MTU 1010/JGL 3844 (short stature), BPT 5204/NLR 34449 (number of tillers and panicles), BPT 5204/MTU 1081 (panicle length), MTU 1010/MTU 1075 (1000-grain weight) and BPT 5204/MTU 1075 (grain yield per plant).