Combining ability analysis for seed and seedling vigor traits in rice (oryza sativa l.)

Combining ability analysis was made in a 7x7 diallel cross for rate of germination index, seedling root length, seedling shoot length and seedling dry weight. Variances of general and specific combining ability were highly significant for all the traits indicating both additive and non-additive type of gene action. Higher magnitude of variances due to 'gca' suggested preponderance of the additive type of gene action except for seedling dry weight. IR25924-92-1-3 and TNAU (AD) 103 were good general combiners for rate of germination index where as IR50 and IR31779-19-3-3-2 were good general combiners for most of the traits studied. TNAU (AD) 103 x M148 and IR50 x IR9764-45-2-2 were the best specific combinations for R.G index. The best combinations R.G. index for seedling root length, seedling shoot length and seedling dry weight were TNAU (AD) 103 x M 148, IR9764-45-2-2 x M148, IR21820-154-3-2-2- x M148 and IR9764-45-2-2 x M148 respectively. (author)