Study of Genetic Diversity and Drought-Tolerance Characteristics of Few Rice Varieties Using Morphological and Molecular Markers

Rice (Oryza sativa L.) is one of the most important cereal crops. Increasing rice production is constrained by various stresses and drought is one of the major limiting factors. For future food security, assessments of genetic resources are necessary. Indigenous varieties contain a high level of genetic diversity and can serve as potential genetic resources for improving yield, and resistance to various biotic and abiotic stress conditions. The present investigation was conducted in the Biotech Hub, Biswanath College of Agriculture, AAU, Biswanath Chariali during 2022-23. In this study, the genetic diversity of 27 indigenous rice germplasm using SSR markers was assessed. Out of the total 28 SSR markers screened, 17 were found polymorphic across twenty-seven genotypes with PIC values ranging from 0.076 to 0.499. The genetic diversity was estimated by the Jaccard dissimilarity coefficient. The phylogenetic tree, using unweighted neighbor-joining (UPGMA) drawn from the analysis divides 27 genotypes into 3 clusters. Nine genotypes were further characterized by exposure to drought stress compared to the control condition. Plants were grown in PVC pipes and subjected to drought by withdrawing water at 45 days after showing (DAS) for 25 days. A comparative study was done for a few morphophysiological parameters i.e. root length, root biomass, root-shoot ratio, root length density, chlorophyll content etc. It was observed that genotype Dehangi followed by N22 and Shahabhagi showed the best performance for all parameters under drought stress. This information will help in the selection of varieties with better root characteristics for drought tolerance in future breeding programs.