Combining Ability for Yield and its Contributing Traits in Rice (Oryza sativa L.) Under Salt Affected Soil

The present study was conducted to assess the gene action, general combining ability and specific combining ability for yield and its contributing traits in rice (Oryza sativa L. ). The experiment was laidout in randomized block design with three replications, at the Genetics and Plant Breeding farm of Narendra Deva University of Agriculture and Technology, Narendra Nagar, (Kumarganj) Faizabad (U. P. ) during kharif, 2013 (under salt affected soil (pH=9.1, EC= 3.2, ESP=41.0). The experiment was based on evaluation of a line x tester set of 36 hybrids (F1s) and their 15 parents along with 2 checks (CSR 43 and FL 478) for nine traits. The analysis of variance for treatments, parents and crosses was highly significant for all the traits indicating the existence of sufficient variability in the treatments, parents and crosses for all the traits. The dominance variance was more then additive variance. In general, maximum contribution to the total variance was due to females higher than due to males for all the traits except days to 50 % flowering and L/B ratio. Among the parents, best genotype was IR55179-3B-11-3 which exhibited significant gca effect for grain yield plant-1, indicating the involvement of additive gene action for yield and component traits. Among the crosses the best hybrids was Narendra Usar Dhan 2009 x NDRK 50026 which exhibited significant sca effect for grain yield plant-1, indicating the preponderance of non-additive gene action for yield and its contributing traits. Results revealed that (2 s) was more than (2 g), degree of dominance greater than 1 and general predictability ratio less than 1 in all the traits, indicating the preponderance of non-additive gene action, emphasizing heterosis breeding for rice improvement under salt affected soil.