Marker-assisted pseudo-backcrossing for developing climate-resilient rice

The increased prevalence of abiotic stresses, such as salt, submergence, and drought, severely affects rice productivity. Developing a rice variety, with inbuilt resistance to these main abiotic stresses, will contribute to a long-term rise in rice yield in adverse environments. In the present study, the rice variety Improved White Ponni (IWP) a high-yielding but highly susceptible to drought, salinity, and submergence variety was introgressed with Sub1 + SalT + DTY2.2 + DTY3.1 + DTY6.1 QTLs for improved abiotic stress tolerance. Foreground markers were employed to select the positive genotypes harboring all five in heterozygote conditions. Among the segregating population obtained from a single plant harboring all the five QTLs phenotypic selection was done to narrow down the plant numbers to 300 based on grain quality. The best lines performing better in all three stresses were subjected to background genome recovery. Five identified superior F₃ lines with more than 80 per cent genome recovery of IWP were discovered to have a medium-thin kernel and an intermediate gelatinisation temperature. Further, among the five, two lines viz., F3-IWP-747-301 and F3-IWP-747- 338 were found to possess all 5 QTLs showing resistance to all three abiotic stresses with enhanced yield. The study's findings amply illustrated the target QTLs' ability to mitigate the effects of salt, submergence, and drought-induced damage, and they also paved the way for creating an IWP variant with resistance to all three stresses.