Genetic analysis of grain micronutrients and yield components in rice (Oryza sativa L.) genotypes
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Date
2022
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DRPCAU, PUSA
Abstract
The present research programme entitled “Genetic analysis of grain micronutrients and yield components in rice (Oryza sativa L.) genotypes”, consisting of 31 genotypes, was conducted at RPCAU Research Farm, Pusa in RCBD with 2 replications, during Kharif (2021-2022). The aim of the research was to assess variation for yield and yield components including grain Iron and Zinc content, to workout causal association of yield components, including grain Iron and grain Zinc content, with grain yield and to Workout genetic divergence among rice genotypes.
The research was conducted by many genetic parameters viz. variability, heritability, genetic advances, association among the different quantitative traits, their direct and indirect influence on grain yield and genetic divergence was worked out using mean values of 13 quantitative traits.
The ANOVA showed presence of extremely significant variations among the all genotypes for all the thirteen traits under experiment. For each of the traits coefficient of variation (GCV and PCV) differed and found to be low indicating the meager influence of environment on the manifestation of these traits. Further, the traits, Plant height, Days to 50% flowering, Number of panicles per plant, Flag leaf length, Number of grains per panicle, Test weight, Grain Zinc content and Grain yield per plant all demonstrated high heritability followed by high genetic advance as percent of mean suggesting that the simple selection measures would be successful for these traits to carry out genetic advancement in the specific direction.
The traits Plant height, Grain Iron content, Grain Zinc content has been showed significantly negative correlation with yield. However, the traits Number of panicles per plant, Panicle length, Number of grains per panicle, Test weight and Kernel breadth showed significant positive correlation with grain yield per plant. These traits may be prioritised in the yield improvement selection procedure due to their significant correlation with grain yield per plant.
The path coefficient analysis has been used to divide the phenotypic correlation coefficient into measures of direct and indirect effect. The findings of phenotypic path coefficient study supported the inference from correlation study revealed that the traits Number of panicles per plant, Panicle length, Flag leaf length , Number of grains per panicle and Test weight are major determinants of Grain yield per plant as they showed direct positive effect (0.211, 0.283, 0.123, 0.156 & 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 31 genotypes were divided into 06 clusters. The trait Number of grains per panicle, followed by traits grain yield per plant and test weight were found maximum contribution towards varietal diversity and all other traits found approximate equal minor contribution towards varietal diversity. The inter cluster distances were found to be higher than the intra-cluster distances suggesting the genotypes grouped in different clusters were diverse than those included within same cluster. Maximum inter-cluster distance was exhibited between cluster III and cluster V (366.88), followed by cluster II and cluster VII (339.91). The lowest inter cluster distance was observed between cluster III and VI (1305.16). 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%, CR 2818-1-11-1-B-1-1-2-B-1 (26.39 g.), NVSR 522 (25.47 g.), Samba Mahsuri (23.13 g.), CSR HZR 17-8 (22.07 g.), MTU 1356 (21.99 g.) and R-RH2-M1-93 (21.92 g.) outyielded the local check Rajendra Bhagwati(18.43 g.). Two genotypes were significantly shorter than the check variety Rajendra Bhagwati (106.00 cm). R-RHZ-MB-119 was the shortest genotype followed by CR 2818-1-11-1-B-1-1-2-B-1 genotype implying its potential to be used for development of short stature varieties.However, one entry i.e. MI 127 (29.35 ppm) possessed higher grain zinc content than Rajendra Bhagwati (21.20 ppm). Hence, these genotypes can be utilized as parents in crop improvement programmes for biofortification.