Forty-four yellow sarson hybrids developed by line x testers mating design (3 pistillate lines x 9 male parents) were studied along with parents and a standard check for heterosis of yield determinant characters in two environments [Genetics and Plant Breeding Farm (E1), Kumarganj and CRS, Masodha (E2)]. Significant desired heterobeltiosis ranged from 4.52 to 44.86 per cent in E1 and 13.42 to 62.07 per cent in E2 while, standard heterosis ranged from -6.64 to 23.01 per cent in E1 and -6.30 to 21.85 per cent for seed yield plant-1 . Other characters also showed considerable heterosis over better parent and standard check. The crosses L2 x T1 and L3 x T1 were identified as potential for commercial exploitation of heterosis both for seed yield plant-1 and oil content. High heterotic hybrids in both the environments viz., L8 x T1 and L9 x T1 showed stability in performance for nine characters including seed yield plant-1 where as among parent NDYS-141 showed near unity ratio of stability factor for five characters. L9 x T1 followed by L8 x T1 could be identified as most promising crosses on the basis of stability, per se performance, standard heterosis, high GCA and significant SCA effects.