Estimation of indica-tropical japonica genome proportion in wide compatible restorer lines derived through inter sub specific hybridization and molecular diversity analysis among rice genotypes

Abstract

The present investigation was carried out to estimate indica-tropical japonica genome proportion in two newly developed wide compatible restorer lines (RP6367 and RP6368) derived through indica-tropical japonica crosses and to study the molecular diversity among 12 rice genotypes namely, five promising indica restorers (RPHR1005, RPHR1096, IBL57, DR714-1-2 and Akshayadhan), two maintainers (IR58025B and APMS6B), two newly identified wide compatible restorer lines (RP6367and RP6368), two typical tropical japonica lines (IRGC66651 and IRGC66577) and one typical indica genotype (Nagina22) using 50 SSR markers and 45 InDELs. Out of the 95 markers, 54 were found to be polymorphic. The genotypic data of 54 polymorphic markers was used to estimate indica-tropical japonica genome proportion in derived lines and molecular diversity among 12 genotypes. The percentage of tropical japonica genome proportion in derived lines RP6367 and RP6368 was found to be 50% and 55.55% respectively. Our results suggest that the proportion of tropical japonica in hybrid rice parental lines is the key to select the best parents for efficient utilization of the heterosis present between indica and tropical japonica subspecies. Out of the 54 markers, 19 markers recorded PIC value above 0.5 and can be considered as highly informative and useful to study molecular genetic diversity. In this study, the SSRs primers showed higher PIC values compared to InDels. It is concluded that the use of highly polymorphic molecular markers detected in this study gives a better understanding of genetic relationship among closely related rice genotypes.