Genetic Variability and Character Association for Yield-contributing and Grain Quality Traits in Rice (Oryza sativa L.) Genotypes
Surendra Dhami
*
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
D. C. Baskheti
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
Kapil Dhanik
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
Nimish Kala
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
Rupa
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
Kirrti Mohta
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
Vinod Chandra Bhatt
Agronomy, Rajendra Prasad Central Agriculture University, Samastipur, Bihar-848125, India.
Arindam Mandal
Genetics and Plant Breeding, G.B. Pant University of Agriculture and Technology, Pantnagar (U.S. Nagar)-263145, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: To assess the magnitude of genetic variability and to determine character associations and the direct effects of yield-contributing traits on grain yield per plant (GYP) in rice genotypes, while characterising variability in grain quality attributes.
Study Design: Randomised Block Design with three replications.
Place and Duration of Study: Norman E. Borlaug Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar, during Kharif 2025.
Methodology: Thirty-two rice genotypes were evaluated for 13 yield and yield-contributing traits and 12 grain quality traits. Analysis of variance, phenotypic and genotypic coefficients of variation, broad-sense heritability, genetic advance, genetic advance as a percentage of the mean, phenotypic and genotypic correlations, and path coefficient analysis were conducted.
Results: Genotypes differed significantly (P < .01) for all 25 traits. PCV was highest for number of sterile spikelets (71.68%), harvest index (32.88%), grain yield per plant (30.93%), alkali digestion value (24.76%), number of fertile spikelets (24.21%) and biological yield per plant (20.61%). Broad-sense heritability ranged from 32.44% for plant height to 98.91% for number of fertile spikelets. High heritability coupled with high GAM was observed for days to 50% flowering, flag leaf area, number of effective tillers, number of sterile spikelets, number of fertile spikelets, number of grains per panicle, biological yield per plant, grain yield per plant, harvest index and thousand grain weight. Grain yield per plant showed significant positive phenotypic and genotypic correlations with flag leaf area (rp = .49, rg = .54), panicle length (rp = .28, rg = .36), number of fertile spikelets (rp = .29, rg = .30) and harvest index (rp = .78, rg = .80), while days to 50% flowering and plant height were negatively associated with grain yield per plant. Among the yield-related traits in the study, flag leaf area, thousand grain weight, number of grains per panicle, and number of effective tillers showed strong positive direct effects.
Conclusion: The evaluated material possessed substantial exploitable variability. Flag leaf area, number of effective tillers, number of fertile spikelets, panicle length, harvest index, thousand grain weight and number of grains per panicle constitute useful traits for selection aimed at improving grain yield. Several genotypes also showed desirable quantitative grain-quality attributes.
Keywords: Rice, Oryza sativa L., genetic variability, heritability, genetic advance, grain yield, character association, path coefficient analysis, grain quality