Genetic architecture, interrelationship and path analysis for yield improvement in Exotic rice (Oryza Sativa L.)

A study of genetic variation and inter-relationship among grain yield and its component traits in rice (Oryza sativa L.) was carried out using 64 exotic rice genotypes. The maximum GCV and PCV was exhibited by number of spikelets per panicle followed by number of productive tillers per hill, harvest index and flag leaf length whereas rest of the traits showed moderate GCV and PCV. High heritability was recorded for all the traits studied except flag leaf width. High estimates of heritability coupled with high genetic advance as per cent of mean was observed for all the traits studied except flag leaf width whereas flag leaf width exhibited low heritability along with low genetic advance as percent of mean. The component traits viz., plant height, number of productive tillers per hill, biological yield per hill and harvest index showed positive and significant correlation with seed yield per hill at both genotypic level and phenotypic level. The maximum direct effect towards the total correlation with seed yield per hill was observed for harvest index followed by days to maturity and test weight. The direct contribution of days to 50 per cent flowering and flag leaf width was positive but low in magnitude. The strong positive correlation between component traits and seed yield per hill with high direct effect indicating the true relationship between them, therefore direct selection though this trait will be effective for yield improvement.