Abstract

                                Gene action and combining ability for yield and yield components of aromatic rice were studied by line x tester analysis in twelve crosses involving four induced mutants of two traditional cultivars as lines and three 'basmati' varieties as testers. Additive gene action was predominant for days to flower, panicle number/plant, filled grains/panicle, test weight and grain yield/plant, while nonadditive gene action was predominant for plant height, dry matter production/plant and harvest index. Mutants of Tulaipanja 88-8-3 and 33-9-15, were good general combiners for plant height and test weight, while mutants of Gobindabhog, 124-17-4 and 21-6-1, were good general combiners for days to flower and filled grains/panicle. Mutants 88-8-3 and 124-17-4 were best general combiners for grain yield/plant. Difference in combining ability between the mutants originating from same parent was due to radiation induced changes. Among 'basmati' varieties, Pakistan Basmati was good general combiner for most of the important characters including grain yield/plant. The hybrid 21-6-1/Pakistan Bastmati alone, was the best specific combiner for grain yield/ plant.

Key words : Combining ability, Gene action, Agronomic traits, Induced mutants, Aromatic rice.