Studies on interrelationship and genetic variability for yield and its contributing traits in rice (Oryza sativa L.)

Abstract

An experiment was carried out to assess the interrelationship, genetic variability, heritability, genetic advance and direct and indirect effects for yield and yield contributing traits using twenty five genotypes of rice at Crop Research Centre (CRC) Chirodi, SVPUA&T, Meerut, UP during Kharif 2021 in RBD. Analysis of variance showed significant amount of variability for all ten traits under study in 25 rice genotypes. High GCV and PCV (>20%) were observed for grains per panicle. High heritability was observed for plant height followed by days to maturity, grain per panicle, days to 50% flowering, biological yield per plant, no. of tillers per plants., grain yield per plant, harvest index, panicle length per plant , test weight. high heritability coupled with high genetic advance as percent of mean was recorded in plant height, grain per panicle, no. of tillers per plants, harvest index showing that heritability might be due to additive gene effects and direct selection for this trait may be useful. Genotypic correlation coefficients were higher than the phenotypic correlation coefficients in all the traits under study indicating that the removal of environmental influences strengthened genetic association and that these characters are positively governed by additive gene action and are helpful in genotype improvement. Grain yield per plant showed positive and significant correlation with no. of tillers per plants, test weight, plant height, biological yield per plant, harvest index, and panicle length per plant both genotypic and phenotypic level. Thus, presence of several contrasting types of inter-relationships simultaneously would bring improvement in others due to correlated responses. Path coefficient analysis for direct and indirect effects on yield revealed significant high direct effect for biological yield per plant, harvest index, Panicle length per plant, Grain per Panicle and No. of tillers per plants at both genotypic and phenotypic level. Path analysis revealed that biological yield per plant (1.07) and harvest index (1.06) had the highest direct effect on grain yield per plant. Based on D2 values twenty five genotypes of rice were grouped into five clusters using ten component characters. Cluster III contained maximum number of genotypes (Ten) followed by cluster V containing 6 genotypes. Cluster II containing 4 genotypes While cluster I also comprising 4 genotypes Cluster IV containing only one genotype. Cluster IV containing only one genotype i.e. Improvad Pusa basmati-1 which independently diverged from others. The inter-cluster distance was greater than the intra-cluster distance. Which reveals considerable genetic diversity between the genotypes examined. Within the cluster is the largest in cluster V (D2 = 2.605), showing the largest genetic diversity, followed by cluster IV (D2 = 2.177) and cluster II (D2 = 2.118). Distance between clusters (D2) is the main criterion for genotyping. The inter-cluster D2 value for the five clusters is that the maximum distance generalized between clusters is (D2 = 6.876) between cluster I and cluster III, followed by cluster I and II (D2 = 5.385) shows that it showed divergence. The lowest (D2 = 3.324) is between Cluster II and Cluster IV, indicating a close relationship and similarity to most characteristics of all genotypes in these clusters. The significant difference in cluster means for several traits was another method of determining the genotypes' diversity. The Cluster I had highest mean values for days of maturity (89.50), plant height (54.77) and 50% flowering (39.50). Cluster mean values of II had highest for days of maturity (87.12), plant height (81.27). Genotypes in cluster III had highest mean values of days of maturity (92.5), plant height (70.77) and 50% flowering (48.50). Cluster V had highest mean values for days to maturity (90.50). Cluster mean values of IV had highest for days to maturity (95.57)and 50% flowering (51.48).