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

Abstract

Sixty-nine cultivars of rice were examined for fourteen biometrical characteristics to study the degree of genetic divergence, heritability and genetic gain as a percentage of mean, character relationship and path coefficient 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 seedsper panicle and flag leaf length indicating that these traits may be given importance while exercising selection. Plant height, panicle length,total tillers, total effective tillers per plant, flag leaf length, grain length, grain L/B ratio, the number of filled seeds per plant, hundred seed weight and yield per plant 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 to 50% flowering,total tillersper 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 plant asserting that these traits were the most efficient and promising selection criteria. Keywords: Rice, PCV, GCV, heritability, genetic gain, correlation and direct effects&nbsp