Genetic evaluation of rice (Oryza sativa L.) genotypes for grain micronutrients and yield components
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Date
2022
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DRPCAU, PUSA
Abstract
The present research programme entitled “Genetic evaluation of rice (Oryza sativa L.) genotypes for grain micronutrients and yield components”, consisting of 38 genotypes, was conducted at RPCAU Research Farm, Pusa in RCBD with 2 replications, during Kharif (2021-2022). The goal of research was to assess variability for yield and yield components including grain Iron and Zinc content, to workout the causal relationship of yield components including grain Iron and Zinc content with grain yield and to workout genetic divergence across rice genotypes.
The research was performed with many genetic parameters viz. heritability, variability, genetic advances, association among the different traits, their effects like indirect & direct effects grain yield, and genetic divergence was worked out using mean values of 13 quantitative traits.
The ANOVA showed existence of extremely significant variations between the all genotypes for all the thirteen traits under experiment. The GCV and PCV differed slightly with narrow gap for all the traits and were showing the very small effect of environment on the expression of these thirteen quantitative traits. Further, the traits, Number of panicles per plant, Plant height, Flag leaf length, Number of grains per panicle, Days to 50% flowering, Test weight, Grain yield per plant and Grain Zinc content showed high heritability together with high genetic advance as percent of mean and it is suggesting that simple selection measures would be successful for these quantitative traits to carry out genetic advancement in the specific direction.
The traits Grain Iron content, Plant height and Grain Zinc content showed negative significant correlation with grain yield per plant. While, the traits, Number of grains per panicle, Panicle length, Test weight, Number of panicles per plant and Kernel breadth showed positive significant correlation with grain yield per plant. For yield advancement these traits may be given preference in the selection activity for yield improvement, for the reason that they showed strong association with trait grain yield per plant.
The path coefficient analysis was used to divide the phenotypic correlation coefficient into measures of direct and indirect effect. The results of phenotypic path coefficient study supported the inference from correlation study revealed that the traits, Flag leaf length , Panicle length, Number of grains per panicle, Number of panicles per plant, and Test weight are main determinants of Grain yield per plant. Owing to that, they showed direct positive effect (0.123, 0.283, 0.156, 0.211, & 0.287 respectively).
Diversity study was carried out using Mahalonobis’s D2 analysis, and the clustering of genotypes was carried out using Euclidean’s method. All the 38 genotypes were divided into seven clusters. The trait Panicle length were found maximum contribution towards varietal diversity and all other traits found approximate equal minor contribution towards varietal diversity. The genotypes that were placed in separate clusters were more diverse than those included in the same cluster, as according to the findings that the inter-cluster distances were larger than the intra-cluster distances. Inter-cluster distance was exhibited in between cluster number VII and cluster IV (537.17) was found to be highest, after that in between cluster II and cluster VII (339.91). Cluster I and VI was found as the lowest inter cluster distance (116.89). So, genotypes from these cluster-pairs with larger cluster mean difference may be utilized for crossing to get better recombinants.
Considering the per se performance and CD at 5%, R-RHZ-SK-128 (26.97 g.), CR 2818-1-11-1-B-1-1-2-B-1 (26.22 g.), Samba Mahsuri (26.04 g.), R-RH2-M1-93 (24.62 g.) and R-RHZ-IR-140 (23.14 g.) outyielded the local check Rajendra Bhagwati(18.98 g.) while ten entry i.e. R-RHZ-SM-14 (32.75 ppm), Zinco rice (31.375 ppm), CGZR-1 (28.3 75 ppm), R-RHZ-IR-132 (27.5 ppm), CSR HZR 17-8 (26.85 ppm), R-RHZ-IH-82 (26 ppm), CSR HZR 17-42 (25.95 ppm), R-RHZ-IB-80 (25.35 ppm), DRR Dhan 49 (25.25 ppm) and CR Dhan 311 (25.15 ppm) possessed higher grain zinc content than Rajendra Bhagwati (22.20 ppm). Out of these ten genotypes superior for grain Zinc content, seven genotypes namely R-RHZ-IH-82 (26.00 ppm), DRR Dhan 49 (25.25 ppm), R-RHZ-IR-132 (27.5 ppm), CSR HZR 17-42 (25.95 ppm), CGZR-1 (28.3 ppm), R-RHZ-IB-80 (25.35 ppm) & CR Dhan 311 (25.15 ppm) were also founds at par with grain yield per plant. Only one of the entry i.e. R-RGY-MH-113 (11.8 ppm) was found superior for grain Fe content than local check Rajendra Bhagwati (9.55 ppm). This suggests the potential of this genotype as biofortified rice variety.