Molecular Diversity Analysis and Screening of Drought Tolerance Rice (Oryza sativa L.) based on Morpho-physiological and SSR Marker

Background: Drought prone areas have been increasing day by day because of raising temperature or heat . The assessment of genetic divergence existing in the germplasm collections is very important for success of hybridization programme leading to development of high yielding varieties under drought stress condition. Methods: The present investigation comprising of 123 rice genotypes was carried out at LPU Phagwara punjab in Kharif 2022 and plants were grown in augmented design under controlled environment. 28 SSR markers were selected for the genetic diversity analysis. The software NTSYS-pc version 2.1 (Exeter Software, Setauket, NY) was used for the statistical analyses of the morphological and SSR marker data. Result: The analysis of variance for genotypes was reported to be highly significant for all the charcters studied. This indicated sufficient variability available among the genotypes. The leaf rolling was recorded by visual observation in the field condition in the scale 0 to 9 to screen for drought tolerance. The molecular diversity analysis and clustering of diverse rice germplasm into different groups confirm the presence of wide genomic variation among selected genotypes. The range of polymorphic information content (PIC) varied from 0.352 (RM204) to 0.698 (RM480). The markers RM480, RM170, RM316 and RM20 were found most appropriate for discriminating rice genotypes owing to their highest PIC values (0.690 to 0.698). The genotypes were grouped to construct a dendrogram by using the unweighted pair group method based on Arithmetic. In cluster II most of the moderately tolerant genotypes were included, while in cluster III highly tolerant 11 genotypes were grouped. The UPGMA clustering also correlated with drought tolerance characters such as days to maturity, leaf rolling and chlorophyll content, proline content and relative water contents. The genotypes APO, RASI and Nagina-22 were observed to be highly tolerant of drought stress conditions. Among the genotypes, Vandana, Rajendra Bhagwati and RAU-3 were moderately tolerant whereas BPT-5204, MTU-7029 and Sarjoo-52 were susceptible to drought stress. Four genotypes viz. APO, RASI, Nagina-22 and RAU-4 can be used as a source of drought-tolerant genotypes for further breeding programs.