GENETIC STUDIES IN HIGH PROTEIN LINES OF RICE (Oryza sativa L.)
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Date
2023-12-04
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Acharya N G Ranga Agricultural University
Abstract
The present investigation entitled “Genetic studies in high protein lines of rice (Oryza sativa L.)” was carried out during Kharif, 2021 at Indian Institute of Rice Research farm, ICRISAT, Hyderabad with 31 genotypes of rice consisting of 30 landraces and one released variety, CR DHAN 310 as check in a randomized block design with three replications and observations were recorded on grain yield, yield component and quality characters.
Analysis of variance revealed significant differences among the genotypes for all characters studied, indicating the existence of sufficient variation among the genotypes studied. Studies on mean performance of the genotypes revealed the genotypes, JAK 374, JAK 124 and JAK 390 to be on par for grain yield, protein content, iron content and amylose content, compared to the check, CR DHAN 310.
The studies on variability, heritability and genetic advance as per cent mean thus revealed high GCV and PCV for grains panicle-1 and iron content, High heritability coupled with high genetic advance as per cent mean was recorded for plant height, ear bearing tillers plant-1, grains panicle-1, grain yield plant-1 and iron content indicating, the effectiveness of simple selection for improvement of these traits.
The results on character associations and path analysis revealed positive and significant association coupled with high positive direct effect for ear bearing tillers plant-1, panicle length, grains panicle-1 and amylose content indicating the effectiveness of direct selection for these traits in improvement of grain yield plant-1. However, for test weight , days to 50 per cent flowering, plant height, head rice recovery (%) and zinc content, indirect effects seemed to be the cause of correlation and hence, consideration of indirect causal factors is suggested for these traits, while for days to maturity, protein and iron content, the use of restricted simultaneous selection model is suggested with restrictions imposed for nullifying the undesirable indirect effects in order to make use of the high positive direct effect observed for these traits on grain yield plant-1.
Studies on genetic divergence using Mahalanobis D2 resulted in grouping of the genotypes into six clusters. Maximum inter-cluster distance was observed between
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genotypes of Cluster V (JAK 14, JAK 611, JAK 638 and JAK 552) and with JAK 248-3 of Cluster VI, while intra-cluster distance was noticed to be maximum for the genotypes in Cluster V. Cluster VI had recorded maximum grain yield plant-1, panicle length, grains panicle-1, test weight and zinc content. The Cluster V had recorded highest protein content. Hence, hybridization between Cluster V and Cluster VI genotypes is suggested for utilization in breeding programmes aimed at the development of high yielding rice genotypes with good protein content.
Studies on PCA revealed five Principal Components with eigen value greater than one having cumulative percent variance of 67.69. The traits, grain yield plant-1 and iron content were found to contribute maximum towards existing variability.
Molecular diversity studies using 15 SSR markers revealed eight SSR markers to be polymorphic for the genotypes studied. The markers, RM80 and RM163 recorded highest PIC value of 0.58. The cluster analysis using UPGMA (Unweighted Pair Group Method with Arithmetic Averages) algorithm grouped the 31 genotypes studied into three major clusters i.e., Cluster I, II and Cluster III. Further Cluster I, was subdivided into Cluster IA and Cluster IB, Cluster II was subdivided into Cluster IIA and Cluster IIB and Cluster III was subdivided into Clusters IIIA and IIIB. The mode of distribution of genotypes into various clusters was observed to be random with no relation to geographical diversity.
The study identified JAK 374 as a promising high yielding, long duration, semi-dwarf landrace with high protein content, on par with CR DHAN 310 along with significantly lesser plant height and test weight in addition to on par panicle length, grains panicle-1, head rice recovery (%) and zinc content for potential commercial exploitation, while JAK 124 and JAK 390 are identified as short duration, semi-tall high yielding genotypes with nutritional quality on par with CR DHAN 310.