Characterization and Heterotic Grouping of Traditional Assam rice (Oryza sativa L.)

Parents of heterotic hybrids are derived from different heterotic groups with high genetic divergence. Classification of traditional Assam rice germplasm in divergent pools will be advantageous to maximize the heterosis and thereby to ensure food security. In the present investigation, a group of 60 upland rice genotypes were characterized using 53 polymorphic simple sequence repeats (SSR) markers out of 83 molecular markers. The genetic divergence study using unweighted Neighbour-joining (UNJ) method clustered the 60 genotypes into 3 major clusters. The eleven most divergent genotypes identified were crossed in half diallel fashion to determine the mid-parent and better-parent heterosis values for the objective of heterotic grouping. No correlation between heterosis and genetic distance can be attributable to the use of a subset of markers not linked to yield or concerned. In genetic distance based heterotic grouping, the intra-group hybrids were recorded a higher frequency of crosses, grain yield per plant, specific combining ability effect, mid parent heterosis, better parent heterosis and standard parent heterosis value than those of inter-group hybrids. Overall, sn extensive choice of parents with attractive traits constellation leading to increased yield of the hybrids for much better complementation must be stressed along with a substantial hereditary distance for augmentation of yield heterosis.