Evaluation of Rice Recombinant Inbred Lines Developed from the Cross Rasi × Improved Samba Mahsuri for Drought Tolerance

Abstract

Drought has been one of the most important limiting factors for rice productivity, particularly in the rainfed ecosystem. It is important to understand the genetic basis of drought tolerance in donor lines and develop drought tolerant rice cultivars, based on this information. We earlier identified the rice line, Rasi as tolerant to drought and developed a recombinant inbred line (RIL) mapping population consisting of 209 lines. These lines along with their parents were grown under well-watered and drought stress conditions in a two-year experiment (wet season 2020 and 2021) with drought stress imposed during reproductive stage. The study revealed high genetic variability for 12 key agro morphological traits associated with drought tolerance among the RILs.  Of the 209 RILs, 59 showed superior performance over the checks and even the tolerant parent, Rasi under severe drought condition. Two RILs, RIL-33 and RIL-58 showed exceptional drought tolerance along with greater plot yield and grain weight under drought condition and they possessed medium slender grain type. These two lines can be a new novel genetic resource for drought tolerance in breeding programmes.