Combining ability studies in rice

Four well adapted lines and eight testers of rice were crossed in Line xTester fashion to elicit information regarding the desirable parents and crosses for their use in crop improvement programme. Sufficient genetic variability was observed among the parents, lines and crosses for all the traits studied. Analysis of variance revealed significant differences among genotypes, crosses, lines, testers and lines x testers interaction for tiller number, plant height, days to 50% flowering, panicle length, number of spikelets panicle−1, spikelet fertility and grain yield. Variance of SCA were higher than GCA variances for all the traits except for number of filled spikelets panicle−1 which indicated predominance of additive gene action in the inheritance of these traits. The estimates of gca effects revealed that the genotype Pusa-5A among the lines and Dubraj (nagri) among the testers were found to be the best general combiners for grain yield plant−1 and its components. Significant sca effect was exhibited by three crosses viz. PMS-11A/Basmati -370, PMS-11A/MTU-1001 and CRMS-32A/Dubraj (nagri).