STUDIES ON GENETIC DIVERSITY AND FERTILITY RESTORATION OF PARENTAL LINES THROUGH MOLECULAR MARKERS IN HYBRID RICE (Oryza sativa L.)
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Date
2019
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PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY
Abstract
The present investigation entitled “Studies on genetic diversity and fertility restoration of parental lines through molecular markers in hybrid rice (Oryza sativa L.)” was undertaken at Indian Institute of Rice Research farm, Rajendranagar, Hyderabad during Kharif, 2018 were evaluated for morphological diversity, fertility restoration and to estimate genetic parameters for yield and yield related traits.
Analysis of variance revealed significant differences for all the traits studied indicating the presence of sufficient amount of genetic variability among 64 parental lines. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for number of productive tillers per plant, number of filled grains per panicle and grain yield per plant. High heritability coupled with high genetic advance as percent of mean was observed for plant height, number of productive tillers per plant, number of filled grains per panicle, test weight and grain yield per plant, indicating the influence of additive gene action, as such simple selection could be likely be effective for improvement of these characters.
Sixty four parental lines were grouped into seven clusters through Mahalanobis D2 statistics. Genotypes belonging to cluster III having maximum intra cluster distance can improve the yield. The genotypes belonging to cluster V and VI, cluster V and VII, cluster III and VII have had maximum inter cluster distance. It is indicated that hybridization between the genotypes (SD-43) of cluster V and cluster VI (GR-7), cluster V (SD-43) and cluster VII (SD-46), cluster III (HSRV-16, GR-29, HSRV-1 and ATR-394) and cluster VII (SD-46) can be used as parents in the further crossing programmes. Through cluster mean analysis it is concluded that cluster VI had highest mean value for number of filled grains per panicle. The genotypes from the clusters having high mean values may be directly used as parents for further hybridization programme. Relative contribution of different characters towards total genetic divergence indicated that the diversity was more for 1000 grain weight and number of grains per panicle suggesting their importance in contribution towards genetic divergence.
A total of four fertility restoration (Rf3 and Rf4) markers such as RMS-PPR-9-1, RMS-PPR-762, DRRM-RF3-10 and RMS-SF-21-5 were analyzed with sixty four parental lines and out of which 44 genotypes were found positive with all the four markers. These 44 genotypes were HSRV-1, HSRV-4, HSRV-5, HSRV-6, HSRV-16, GR-2, GR-6, GR-9, GR-11, GR-14, GR-15, GR-22, GR-29, GR-37, GR-40, P-63, TCP-583, TCP-718, TCP-950, TCP-964, TCP-1369, TCP-1483, TCP-2069, ATR-394, RPHR-2, RPHR-619-20, RPHR-1005,IBL-57, DP-207, DP-230, SD-4, SD-57, SD-64, SD-66, SD-67, SD-5, SD-2, SD-7, SD-9, SD-49, SD-62, SD-73, SD-77, BCW-56.
The character association studies revealed that grain yield per plant showed positive significant association with number of productive tillers per plant, panicle length and number of grains per panicle. Path analysis revealed that number of grains per panicle exhibited highest direct effect on grain yield followed by number of productive tillers per plant, test weight, panicle length, plant height and days to 50% flowering.
It can be concluded that high variability, high heritability coupled with high genetic advance as percent of mean and positive significant correlation observed for productive tillers per plant. Increase in number of productive tillers per plant in restorers is expected to yield improvement in derived hybrids. Among the seven clusters, the clusters II, IV, V, VI, and VII were represented by single genotype namely GR-37, IBL-57, SD-43, GR-7 and SD-46 indicating high degree of divergence among the genotypes. These restorers can be directly used as parental lines in development of heterotic hybrids for irrigated and unfavorable ecosystems. Forty four genotypes were found positive for fertility restoration (Rf3 and Rf4) genes with the entire four gene based markers, which indicates that efficiency of molecular markers in identifying restorers and its deployment in hybrid rice breeding programme.