Genetic variation of yellow‐seeded rapeseed lines (Brassica napus L.) from different genetic sources

Abstract In order to breed yellow‐seeded rapeseed, 16 yellow‐seeded lines of Brassica napus L. derived from eight genetic sources were used. The genetic variation of the seedcoat ratio, the cellulose content of the seedcoat, the oil content of the seedcoat and of the embryo, and also the correlations between these characters of the yellow‐ and brown‐seeded plants from the same line, were analysed by variance analysis and path analysis. The results show that the seedcoat ratio and cellulose content of brown seeds are 4.2% and 17.74%, respectively, higher than that of yellow seeds and the oil content of the seedcoat of brown seeds is 3% lower than that of the yellow seeds, these differences all being highly significant. However, the differences between yellow and brown seeds in 1000‐seed weight and oil content of the embryo were very small. Both characters are determined mainly by the genetic background and not by seed colour or seedcoat thickness. The correlation analysis revealed that the seedcoat thickness has a highly significant positive correlation with the cellulose content of the seedcoat and is highly significantly negatively correlated with the seedcoat oil content and the 1000‐seed weight. The oil content of the embryo alone has a highly significant negative correlation with 1000‐seed weight. In yellow seeds, the seedcoat thickness has a large and directly positive effect on the oil content of the embryo whereas the 1000‐seed weight has a negative one; the opposite was found in brown seeds. Selection objectives in breeding yellow seeds in Brassica napus are also discussed.