Studies on Genetic Variability, Divergence and Characters Associated with Yield Components in Rice

Abstract

The current study was carried out to evaluate genetic factors such as  Genotypic Coefficient of Variation (GCV), phenotypic coefficient of variation (PCV), heritability and genetic advance (GA) along with correlations, path coefficients and Genetic divergence from data collected on 22 rice genotypes. The results demonstrated significantly significant mean squares owing to genotypes for all variables investigated, demonstrating that there is adequate variation among genotypes and thus ample possibility for successful selection. Only seed yield per plant showed a high Phenotypic Coefficient of Variation (PCV). Moderate phenotypic coefficient of variation and Genotypic Coefficient of Variation (GCV) observed for number of tillers/plant, number of  spikelets/panicle, flag leaf  length,  flag  leaf  width, number of filled grains/panicle,1000-grain weight and biological yield. High heritability and genetic advance as per cent of mean was observed for number of tillers/plant, number of spikelets/panicle, flag leaf length, flag leaf width, number of filled grains/panicle, 1000-grain weight, biological yield and seed yield per plant, indicating the effectiveness of direct selection for improvement of these traits.  Panicle  length,1000-grain  weight  and  biological  yield  had  recorded  positive  and significant association with seed yield per plant. The results on path analysis also revealed high and positive direct effect for biological yield followed by harvest index, days to 50% flowering, plant height, panicle length and number of spikelets/panicle and hence, these traits were identified as the most effective selection criteria for improvement of seed yield per plant in rice genotypes. The results on divergence analysis revealed that the genotypes were grouped into five clusters. Cluster I constituted maximum number of (10) genotypes. Maximum differences among the genotypes within the same cluster (intra-cluster) were shown by cluster IV (18.33) followed by cluster I, II, III. Cluster V showed zero intra -cluster distance. The genotypes contained in Clusters IV and V (20.20) displayed the greatest intercluster distance, indicating that they might be employed as parents in a future hybridization experiment.