SUMMARY
Combining ability analysis has an important position in rapeseed breeding. To evaluate genetic and combining ability effects, three Brassica napus L. testers “Punjab Sarson, Legend and Durre-NIFA” and five lines “Duncled, K-258, ZN-R-1, ZN-R-8, ZN-M-6” were crossed using line × tester design in Randomized Complete Block Design (RCBD) with three replications. Mean sum of squares of the analysis of variances (ANOVA) for genotypes was highly significant for all of the traits. Most of the lines and testers exhibited significant results of mean sum of squares for combining ability. Line ‘Duncled’ was proved good general combiner for oil (8.8), protein (3.7), erucic acid (33.0), oleic acid (13.0) and glucosinolate (-19.3) over other lines and tester ‘Durree-NIFA’ for protein (6.6), erucic acid (-23.4), and linolenic acid (-5.3) over other testers. Significant specific combining ability effects were also observed. The best hybrid combinations were Legend × ZN-R-1 for oil (9.6), Punjab Sarson × Duncled for minimum erucic acid (-14.0) and linolenic acid contents (-6.0), and Legend × ZN-M-6 for maximum protein (8.2) and minimum glucosinolate contents (-11.1). The maximum oil contents were observed in ‘Legend × ZN-R-1’ (52.4%). The cross ‘Punjab Sarson × Duncled’ expressed maximum values of protein (26.5%) and oleic acid (62.5%) while minimum for erucic acid (2.3%), linolenic acid (5.4%) and glucosinolate contents (19.3µmol/g). This research discloses the significance of non-additive genetic effects for most of the studied traits except oil contents. These studies will also help to improve nutritional values of rapeseed crop by selecting noble crosses.