General Combining Ability Effects of New CMS Lines and Advanced Breeding Restorers and Identification of Best Specific Combiners to Exploit Heterosis in Rice (Oryza sativa L.)

摘要

In an effort to generate information on effects due to combining ability in respect of yield and yield attributes, an investigation was carried out on 160 rice hybrids produced through line x tester mating design using 8 new CMS lines and 20 advancedbreeding restorers used as testers. Analysis of variance revealed that the mean sum of squares due to the lines was significant for all characters except for panicles per plant, panicle length, panicle weight and 1000 grain weight. Among the testers, most of the characters except for panicle weight differed significantly. Estimation of general combining ability (GCA) effects of lines and testers indicated that, no single line or tester was found to be a good general combiner for all the characters studied. However, the lines 5A, 6A and 7A exhibited significant GCA effects in the desired direction for panicles per plant, plant height and spikelets per plant and were considered as good general combiners among lines. The testers, R3 (plant height, panicles per plant, spikelets per panicle and grain yield per plant) R4 (spikelets per panicle, spikelet fertility and grain yield per plant), Rl 1 (plant height and grain yield per plant), Rl 3 (plant height, spikelets per panicle and grain yield per plant), R15 (spikelets per panicle, spikelet fertility and grain yield per plant), R17 (plant height, spikelets per panicle and grain yield per plant) and Rl 9 (plant height, spikelets per panicle and grain yield per plant) were considered as the good general combiners since they had highly significant GCA effects for respective characters. High significant L x T interaction towards total variance emphasizes importance of non-additive gene action in exploitation of heterosis. Ten best specific combiners were selected based on their per se performance. These hybrids also showed high significant SCA variances and can be future potential hybrids.