Abstract:

This paper reports analysis of a 5×4 diallel cross of B. napus L. using GGE biplot. The following patterns were visualized from the biplots. (1) Male sterile lines S2 and S3 had high general combining ability (GCA), and S3 and S1 had high specific combining ability (SCA). Restorer lines R2 and R3 had high GCA, while R2 and R4 had high SCA. The male sterile lines S5 and the restorer R2 were the best parents in terms of both discriminating ability and representativeness. The combinations with high SCA included S4×R4, S3×R1, S3×R2, S5×R3 and S1×R3. (2) Across the sterile lines, the GCA of pods per plant and seeds per pod was positively correlated with the GCA of yield, and the GCA of plant height, 1000-seed weight, and effective branch height was negatively correlated with the GCA of yield. Across the restorer lines, the GCA of pods per plant, pods of main raceme, primary branches, length of main raceme, and plant height were positively correlated with the GCA of yield, whereas 1000-seed weight and effective branch height were negatively correlated with the GCA of yield. Across the hybrids, pods per plant and seeds per pod were positively correlated with yield, while 1000-seed weight and effective branch height were negatively correlated with yield. These results suggest that although good male sterile lines and the restorer lines have different characteristics, more pods per plant, smaller 1000-seed weight, and lower effective branch height are desirable for both. The trait profiles should be complementary between parents to generate superior hybrids.

Key words: GGE bipolt, B. napus L., Diallel cross, Combining ability