Herbicide tolerance is an essential trait for efficient weed management in direct-seeded rice systems (DSR), where early weed competition severely reduces crop establishment and productivity. The present study aimed to elucidate the inheritance pattern of imazethapyr tolerance in rice using F₂ and backcross populations derived from the cross KMP-175 × Robin. Segregating populations were evaluated under field conditions following imazethapyr application at 20 and 30 days after sowing (DAS). In the F2 population, 314 tolerant and 99 susceptible plants were recorded among 413 individuals, fitting the expected 3 : 1 Mendelian segregation ratio (X2 = 0.23, p = 0.63), indicating single gene control. The BCP1 population segregated into 67 tolerant and 61 susceptible plants, conforming to the expected 1 : 1 ratio (X2 = 0.28, p = 0.59), whereas all 95 plants in the BCP2 population exhibited tolerance. The segregation pattern across generations supports that imazethapyr tolerance in Robin is governed by a single dominant gene. Molecular validation using the RM6844 marker linked to the AHAS gene further supports this inheritance pattern. The monogenic dominant nature of the trait enables efficient selection and rapid introgression into elite cultivars. These findings provide a strong genetic basis for developing herbicide-tolerant rice cultivars suitable for direct-seeded production systems.