Abstract / Summary
Abstract Delayed monsoon onset frequently postpones wet-season rice transplanting in drought-prone rainfed environments and may substantially reduce yield. A two-year field experiment was conducted at the Bangladesh Rice Research Institute Regional Station, Rajshahi, Bangladesh, to quantify yield losses caused by delayed transplanting and identify adapted rice genotypes. Six genotypes were evaluated in a strip-plot design with three replications under optimum transplanting at 25 days after sowing (T1) and delays of 10 days (T2) and 20 days (T3). Across genotypes and years, grain yield declined by 11% under T2 and 28% under T3 relative to T1. Genotype-specific daily yield losses ranged from 24–30 kg ha⁻¹ day⁻¹ for IRRI123 to 107–109 kg ha⁻¹ day⁻¹ for Binadhan-7. Delayed transplanting increased the time to flowering and maturity by 6–12 days. Stress tolerance indices and GGE biplot analysis consistently identified IRRI123 and IR83377-B-B-93-3 as stable, productive and comparatively tolerant genotypes. Path analysis indicated that harvest index and reproductive traits were important determinants of yield under delayed transplanting. These results support the use of IRRI123 and IR83377-B-B-93-3 in drought-prone rainfed environments where transplanting is frequently delayed and as potential parental material for breeding programmes targeting combined late-planting and terminal-drought stress.