Molecular Marker-assisted Selection For High Oleic Acid And Low Linolenic Acid Content In The Seed Of Brassica Napus

Brassica napus is a very important source of plant edible oil. The nutritional and economic value of rapeseed oil is largely determined by its relative contents of fatty acids in the seed. Therefore, it has become an important aspect of quality breeding in rapeseed to further increase oleic acid content and decrease linolenic acid content. In this study, the course of backcross breeding was accelerated to obtain the fin lines with high oleic acid and low linolenic acid through marker-assisted selection(MAS). And the genetic background of fine lines got a high recovery of recurrent parent.In this study, we used marker-assisted selection for high-oleic, low linolenic acid content rapeseed in three backcross combinations. Molecular markers related to oleic and linolenic acid content were developed by bulk segregation analysis. Gas chromatography was used for the phenotype identification of oleic and linolenic acid content. The main results are as follows.1. Screening of markers related to oleic and linolenic acidIn the combination of甲A177×甲A254, we detected SSR markers SSR373 and BRGMS630 which were related to oleic acid content according to bulked segregation analysis. In the same way,wo identified SSR markers of BM135,SSR698,BM44-2,SSR128-3 which were related to linolenic acid content. We used the markers to scan correlative QTLs, and got a major QTL related to oleic acid content with the max LOD of 66.1, accounting for 85.61% of the total variance. Genetic distance between the marker BRGMS630 and the max QTL position was 4.4cM, and the genetic distance between the marker SSR373 and the max QTL position was 15.04cM. The two marker were located at both sides of the main-effect QTL.2. Functional verification of the foreground markersWe used DH lines of甲A177×甲A254 to validate the effect of foreground selection by marker SSR373 and BRGMS630. The ratio of false selection of SSR373 was 24.73%, and the ratio of false selection of BRGMS630 was 10.22%.While, we used the SSR373 and BRGMS630 together, the ratio was 5.88%. 3. Selection of genotypes with target characters and highest percentage of background from recurrent parentThe foreground selection was carried out by MAS and gas chromatography. And then, we used SSR and AFLP markers to give background selection of the whole genome. Finally, we got the fine individual 08CW183 in the BC₃F₂ of甲A177×甲A254. The oleic acid content of 08CW183 is 73.95%, and its recovering ratio of genetic background was 94.12%.