|The study was conducted to estimate the genetic variability, heterosis, potence ratio, contribution of lines and testers, general and specific combing ability in canola (Brassica napus L.) for some seed yield and yield contributing traits. Sixteen genotypes (120-R, B9527-1, MANROO, COMET, S-9, KN (20-35), UAF-1, N-RG, 20E, HYBRIPOL, V-22, STAR, 5-F, GOLARCHI, CRS-5, PO-9) were crossed among eleven female parents (lines) and five male parents (testers) in Line × Tester mating design (11x5) during Rabi season 2009-10 and their F1 hybrids were sown in field during Rabi season 2010-11 in randomized complete block design with three replications. Data of fifty five F1 hybrids and their parents were recorded for various seed yield and yield contributing traits, i.e. days taken to 50% flowering, days taken to 50% maturity, plant height, number of primary branches per plant, number of secondary branches per plant, number of siliqua per plant, number of seeds per siliqua, 1000 seed weight and seed yield per plant. The data were statistically analyzed for analysis of variance and Line × Tester analysis and The Results of analysis of variance differences were determine among entries for all the traits at significant level (p ≥ 0.01-0.05). The analysis of variance for combining ability were revealed that the mean sum of squares due to lines were significant for all the traits except plant height and for testers the mean sum of squares were non significant for traits of plant height, number of siliquae per plant and other traits showed highly significant results .Highly significant results were found in line x tester interaction for all traits except the character days taken to 50% maturity. The estimates of SCA variance was noticed higher than GCA variance in all traits. The contributions of lines as compared to testers were greater in case of all the traits. The significant potence ratio were explained the transformation of desirable gene in all traits of genotypes in dominance type of gene action for the development of hybrids and varieties in Brassica napus L.