Marker Assistant-selection For High Oleic Acid Content In Rapeseed (Brassica Napus L.)

Rapeseed(Brassica napus) is the world’s third largest and the China’s No.1oilseed crop. One of the major goals in breeding rapeseed for quality is to improve the composition of fatty acids in oil. Oleic acid is a component breeders are eager to increase in quality rapeseed breeding because of its oxidative and frying stability and health-promoting function. So how to improve oleic acid content under low erucic acid condition is a question to rapeseed breeders. In this study we used mapped markers to more precisely make selection for high oleate Brassica napus, and to accelerate backcross breeding. As a result, we have developed the lines with high oleic acid content and high recovery of recipient’s genetic background at backcross2generation.The six elite rapeseed lines were used as a recurrent parent in this study. The markers flanking two QTLs for oleic acid content from the genetic map previously constructed by our laboratory were used for foreground selection while markers randomly chosen from each of19linkage groups on the genetic map for background selection. Gas chromatography was used for quantifying oleic acid in the seed. The main results are as follows.1. We confirmed that the marker BrA19Y03-BrG23Y13is tightly linked to the QTL for oleic acid content on the linkage group A5while OL12-F02and BrP06Y06are linked to the QTL on C5by genotyping of markers in the region extending from the QTL peak to both ends of a linkage group.2. We developed three classes of introgression lines at BC2F1, i.e. the line with only a single QTL A5-QTL or C5-QTL or with both QTLs for oleic acid content through marker-assisted backcrosses.3. We developed for each of the six recurrent parents elite BC2F1lines whose oleic acid content amounts up to75%as confirmed by half-seed analysis and recovery rate of genetic background reaches up to90%as revealed by background marker genotyping.