Unearthing the genetic potential of drought resilient rice (Oryza sativa L.) landraces through multipronged approaches

Drought has become principle and devastating abiotic stress due to the erratic shifts in climate patterns. Stress breeding programme in rice has extensively explored drought tolerant potential of cultivated indica types. Present investigation aims to ascertain the genetic potential of Indian rice landraces for their drought tolerance ability coupled with high yield. The PEG 6000 concentration of -7.0 bar was standardized as the optimal stress threshold for effectively screening the rice germplasm invitro. Twenty-six rice landraces sourced from NBPGR were subjected to invitro drought screening at -7.0 bar. Based on seedling vigor index at -7 bar, 10 drought tolerant genotypes viz., IC115439, RL4015, RL10330, RL5648, RL6807, RL192, RL10823, RL10844, RL11113 and RL6812 were selected. These genotypes exhibited better performance in terms of vigor index and germination percentage than the drought tolerant checks Anna (R) 4, Apo and Wayrarem. To confirm the phenotypic performance of these selected genotypes in natural environmental condition, they were evaluated under stress in rain out shelter (ROS) and well irrigated field conditions. Evaluation based on biometrical, biochemical traits and drought scores resulted in identification of five landraces viz., IC115439, RL4015, RL5648, RL10330 and RL10823. Among the 26 land races, IC115439, a land race collected from the farmers field of Raipur, was identified to be a valuable pre-breeding resource for drought tolerance breeding in rice.