Genetic variability and relatedness among yield characters in rice landraces and improved varieties

Sixty-nine cultivars of rice were examined for fourteen biomedical characteristics to study the degree of genetic divergence, heritability and genetic gain as a percentage of mean, character relationship and path coefficienl analysis. Yield per plant reported the highest estimate of PCV and GCV followed by the total effective tillers per plant hundred seed weight, number of filled seeds per panicle and flag leaf length indicating that these traits may be giver importance while exercising selection. Plant height, panicle length, total tillers, total effective tillers per plant, flag leal length, grain length, grain L/B ratio, the number of filled seeds per plant, hundred seed weight and yield per planl exhibited remarkable genetic gain and high heritability, implying a predominance of additive gene action. Hence genetic advancement through simple selection would be more beneficial. Among the yield traits examined, days tc 50% flowering, total tillers per plant, the number of effective tillers per plant, flag leaf breadth, the number of filled seeds per panicle, and hundred-seed weight recorded a positive significant correlation with direct effects on yield per planl asserting that these traits were the most efficient and promising selection criteria.