Analysis of genetic variability and character relationship in rice (Oryza sativa L.) seed and seedling traits

Abstract

Eight rice genotypes with different genetic backgrounds were evaluated for grain length, grain width, grain length width ratio, grain thickness, 1000 grain weight, seed germination percent, shoot length, root length and root shoot ratio. The genetic variance (δ^2 g), phenotypic variance (δ^2 p), phenotypic covariance (PCV), genotypic coefficient of variation (GCV), heritability (h_b^2), genetic advance (GA), genetic advance in percent of mean (GA %) and correlation coefficient were all calculated. The experiment was conducted using a Randomized Block Design with three replications in a controlled environment in the laboratory of Department of Agriculture at Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalganj in June 2021. For all of the studied characters, analysis of variance revealed a significant difference in genotypes. PCV values greater than GCV were found in all of the characteristics, indicating that they were influenced by non-additive gene action rather than environmental factors and that selection for improving these traits would be beneficial. The PCV (41.33) and GCV (41.70) estimates for the root shoot ratio were both high, indicating a wide range of variability for the two component characteristics, shoot length and root length. PCV and GCV values were moderate for grain length width ratio, seed germination percent, shoot length, and root length. The PCV and GCV of most grain characters were low. All of the characters had high heritability, ranging from 90.77 percent to 99.81 percent, except for 1000 grain weight (46.91 percent). Seed germination percent (36.03), shoot length (40.03), root length (35.16) and root shoot ratio (35.16) all had high heritability and high genetic advance in percent of mean (79.25). Grain thickness (8.68) and seed germination percent had the lowest GA% (8.71). Grain length with grain length width ratio, grain width with root shoot ratio, 1000 grain weight with grain width, grain thickness, root length and root shoot ratio were all found to have positive and significant correlations in a character association study. At the genotypic level, the highest positive significant correlation was found between 1000 grain weight and root shoot ratio (r_g= 0.908) and grain length and grain width ratio (r_p=0.900). According to genetic variability and correlation analysis, grain length, grain length width ratio, 1000 grain weight, root length and root shoot ratio could be used as selection indices for further improvement of seed and seedling characters of rice genotypes.