Genetic variability and trait association in Jhum Rice of Arunachal Pradesh, India

The study comprised of 19 jhum rice landraces from different parts of Arunachal Pradesh. The analysis of variance based on 14 quantitative traits revealed significant traits-wise variations across the genotypes. Based on cluster analysis the landraces were grouped into 3 distinct clusters. Principal component analysis (PCA) extracted 5 principal components (Eigen value >1) with 80.5 % of the total variance. About 60.4% of the cumulative variance was exhibited by the first three principal components. Traits like grain yield (GY), plant height (PH), primary branch per panicle (PBP), filled grain per panicle (FGP), test grain weight (TGW) and grain morphology exhibit heavy positive loadings in these first PCs. The value of the phenotypic coefficient of variation (PCV) was higher than the corresponding genotypic coefficient of variation (GCV) for most of the traits. The traits exhibits moderate to high PCV, GCV, heritability and genetic advance as a percent of the mean (GAM). High heritability couple with high GAM was exhibited by GY, TGW and PH. While moderate heritability with (GAM) was exhibited by panicle length (PnL), FGP and PBP. Except ligule length (LgL) and flag leaf width (FLW), all the traits displayed positive associations with GY. A high positive significant correlation (P≤ 0.01) was exhibited by grain width (0.716) and TGW (0.583). Path coefficient analysis revealed direct positive effects on GY by girth diameter (GD), flag leaf length (FLL), blade leaf width (BLW), filled grain number per panicle (FGP), TGW, and grain length (GL). The residual effect magnitude of 0.1386 indicated that 99.8 % of the variability was accounted by the traits included in the present study. Thus the study revealed information about the genetic diversity among the jhum rice landraces and associated yield contributing traits for future breeding programme.