Abstract

                                Six lines and five testers were crossed in line x tester fashion and F1 's were evaluated under coastal situation. The ratio between the estimates of additive and dominance variance indicated preponderance of non-additive gene action for all characters studied namely plant height, productive tillers, boot left length, panicle length, grain weight/panicle and grain yield/ plant. Among the parents, ADT 45 recorded significantly superior grain yield/plant and panicle length. This was followed by Swarna and Paiyur I for grain yield /plant. Line parent TKM 11 recorded superior mean for boot leaf length, panicle length and grain weight/panicle. Among the line parents ADT 45 and TKM 11 showed good combining ability for grain yield/plant, panicle length and grain weight/ panicle. It indicates the existence of relationship between per se and gca of parents to certain extend. Among the hybrids, ADT 45 X Vandana, ADT 45 X Nootripathu, ADT 45 X Norungan, ADT 45 X PMK 2, TKM 11 X Vandana, TKM 11 X Nootripathu, TKM 11 X Norugan. TKM 11 X MDU 5, TKM 11 X PMK 2 and Paiyur 1 X PMK 2 recoded significantly superior grain yield/ plant and grain weight/ panicle. With regard to specific combining ability effect, all the superior hybrids recorded additive gene action except ADT 45 X Nootripathu for which additive type epistasis observed. Hence these crosses could be subjected to pedigree breeding to evolve high yielding genotypes for coastal saline situations

Key words : Rice, coastal salinity, combining ability, gene action