Vol. 9, Special Issue 8, Part O (2025)

The present study was conducted by using an Augmented Block Design to screen 201 recombinant inbred lines (RILs) developed from the cross BPT5204 × Arvatellu, along with their parents and standard check varieties like BPT5204, Arvatellu, IR‑4630‑11‑175, KHO, CST7‑1 and CSR‑52 for anaerobic germination tolerance during season kharif (2024-2025) at the Indian Institute of Rice Research (IIRR), Hyderabad. The RILs and parents were phenotypically screened under controlled anaerobic conditions by maintaining a 10 cm water level for duration of 21 days from the date of sowing. Key traits like Germination Percentage (G%), Root Length (RL), Shoot Length (SL), Seedling Height (SH), Culm Diameter (CD), Root Dry Weight (RDW) and Shoot Dry Weight (SDW) were recorded after 21 days from the date of sowing. Significant variation was observed among the RILs. Arvatellu and IR-4630-11-175 consistently showed high tolerance to anaerobic stress conditions. While, CSR-52 and BPT5204 exhibited poor performance under anaerobic conditions. A wide variation was observed in the RIL population (Germination percentage ranged from 7-93%; Root Length ranged from: 3-14.0 cm; Shoot Length ranged from: 14.3-44.2 cm; Seedling Height ranged from 17.0-58.2 cm; Culm diameter ranged from 0.2-1.03 mm; Root Dry Weight ranged from 0.010-0.024 g; Shoot Dry Weight ranged from 0.010-0.026 g). Three RILs namely RIL‑6, RIL‑104, andRIL‑139 were emerged as most promising exhibited superior performance across multiple traits often surpassing the tolerant parents. These RILs hold potential for breeding programs aimed at enhancing anaerobic tolerance in rice. These findings highlight the potential of RILs as a source of Anaerobic Germination tolerance and provide a foundation for future QTL mapping and molecular breeding efforts aimed at improving DSR adaptation.