ASSESSMENT OF GENETIC VARIABILITY, HERITABILITY AND CORRELATION IN SPRING RICE GENOTYPES (Oryza sativa L.) AT RATNANAGAR, CHITWAN IN 2022

The stagnant yield of rice in Nepal can be improved by development of genotypes with improved traits through breeding for which estimates of genetic parameters are essential. Hence, a field experiment was carried out from February to June in the year 2022 with the objectives to evaluate the genetic variability, heritability, genetic advance and character association among yield traits in spring rice genotypes in order to provide valuable insights for rice breeders for the development of high-yielding spring rice varieties. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications comprising 10 genotypes. Various quantitative characters were recorded to estimate variability and correlation coefficient. Analysis of variance indicated significant differences for all traits among the assessed genotypes, indicating the presence of variability among evaluated genotypes. A lower genotypic coefficient of variation than the phenotypic coefficient of variation revealed the presence of environmental influence on the expression of these traits, being higher in fertility percentage and grain yield. High heritability was estimated for all the traits except fertility percentage, harvest index and grain yield. High heritability along with the high genetic advance was reported by the number of filled grains per panicle, thousand grain weight, and straw yield while remaining traits showed moderate to high heritability with low to moderate genetic advance as a percent of the mean. The number of panicles per hill, fertility percentage, biological yield and straw yield exhibited a significant positive association with grain yield indicating the chance of improvement in yield if a selection is applied in favor of those traits among these genotypes. Therefore, the results highlight the potential for selection among these genotypes for traits such as number of filled grains per panicles, number of panicles per hill and straw yield for higher productivity and performance.