Genetic variation and trait association of fine rice genotypes

To explore high yielding genotype and significant yield contributing trait, field experiment was conducted using alpha lattice design replicated three times at the National Wheat Research Program (NWRP), Bhairahawa, Nepal in 2022. Eighteen fine rice genotypes were evaluated based on nine quantitative traits (Heading days, maturity days, plant height, panicle length, effective tillers, filled grains per panicle, unfilled grains per panicle, thousand grain weight and grain yield per hectare). Variance analysis, correlation and estimation of genetic parameters were conducted to comprehend genetic variations and interrelationships among traits within genotypes. The results showed most of traits except unfilled grains had statistical significance differences. Tarahara-107 (3940 kg/ha) had the highest grain yield followed by Tarahara-2 (3700 kg/ha) and NR 2381-RGA1-RGA2 (3665 kg/ha). Similarly, grain yield showed positive and significant association with filled grains at both phenotypic and genotypic level (rp = 0.7074 ** and rg= 0.9482 **). Elevated values of PCV and GCV were recorded for filled grains (22.05 and 17.57). The high value GAM coupled with high heritability was recorded for filled grains (28.83%), plant height (23.10%), number of effective tillers (21.57%) and thousand grain weight (19.37%). Thus, identified genotypes NR 2380-RGA1-RGA2 and NR 2381-RGA1-RGA2 exhibited early and potential high yielding genotypes while Tarhara-107 and Tarhara-2 identified as high yield, medium maturity and good filled grain number per panicle. In addition, filled grains trait displayed tightly linked with grain yield and possess high GCV, PCV, GAM with moderate heritability indicated direct selection could be employed for trait enhancement in breeding program.