Analysis of General and Specific Combining Ability in Canola Using Biplot Method

To study combining ability and genetic parameters of seed yield trait in rapeseed, eight lines of rapeseed were evaluated by a design of half diallel cross. Seeds of F1 generation and their parents were grown in a 6 × 6 simple lattice design with two replications. According to the analysis of variance, general combining ability (GCA), specific combining ability (SCA) and mean squares of genotypes were significant for seed yield at 0.05 and 0.01 probability level, respectively. We used GGE biplot approach for graphical diallel cross analysis. The biplot displays the most important entry by tester patterns of the data and allows the information to be extracted visually. The biplot analysis indicated that the first two principal components explained 74.3% (47.7 and 26.6% by PC1 and PC2, respectively) of the variation for seed yield. GGE biplot graphical procedure results indicated that one parent, Opera, had the highest positive GCA and parents of Fornax had the highest negative GCA. The largest SCA obtained from ORIENT and the smallest SCA came from TALAYE. Also, the SCA mostly came from OPERA and TALAYE, ORIENT and TALAYE. Overall, the results of this study suggest that, within individual hybrid crosses, sufficient heterosis for yield exists to justify hybrid development in rapeseed.