Abstract:
Line (five) × tester (two) analysis was conducted to determine good parents and the nature of
gene action governing yield and its component traits in rice. The line × testers showed significant
differences for all traits except for number of spikelets per panicle and hundred grain weight.
Parents with low × high general combining ability (GCA) effects resulted in heterotic hybrid
combination like the IR62829A/IR57301-158-1R. A low × low GCA gave the best heterotic
combination i.e. IR68888A/’Sepidroud’. The study showed GCA to only identify better parental
lots and it will be unwise to discard the low GCA types. Predominance of dominance gene
action for all the traits studied except for flag leaf width and number of spikelets per panicle
suggests heterosis breeding must be strongly pursued for exploitation of the yield advantage
over the inbred varieties.
