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

Brassica napus is an important economic crop of the world. Rapeseed oil is significant for its edible and industrial value. It is mostly determined by its contents of fatty acids in the seed. So, the crucial aspect of quality breeding is to increase oleic acid content and decrease linolenic acid content, on the base of low erucic acid content. We accelerated the course of backcross breeding in this study, and through marker-assisted selection(MAS), to obtain the fine lines which gets high oleic acid and low linolenic acid contents and the genetic background of fine lines with a high ration of recovery to its recurrent parent. These fine lines are positive for the aspect of quality breeding in rapeseed.The main results are as follows.1. Foreground and background selection in the cross of JA177×JA254Through the selection of the foreground markers and AFLP background markers, there were both 8 individuals with high oleic acid content, and these were correspond to the phenotypic results which detected by the gas chromatography(GC) method. The highest recovering ratio of recurrent parent of the BC4F2 and BC5F2 generation was 97.25% and 98.83%.2. Foreground and background selection in the BC3F2 generation of Zhong9×HOLLY and Hua4×HOLLYThough the selection of the foreground markers and SSR background markers, we got 8 individuals in Zhong9×HOLLY and 9 individuals in Hua4×HOLLY with high oleic acid content, and the corresponding phenotypic results were determined by GC method. The recovering ratio of recurrent parent of Zhong9×HOLLY was 94.21%-98.11%, while the recovering ratio of recurrent parent of Hua4×HOLLY was 93.21%-98.21%.Finally, we got the fine individual #247 in the BC3F2 of Zhong9×HOLLY, and the #2398 in the BC3F2 of Hua4×HOLLY. The oleic acid content of # 247 is 74.16%, and its recovering ratio of genetic background was 98.11%, the oleic acid content of # 2398 is 77.26%, the linolenic acid content is 2.95%, and its recovering ratio of genetic background was 98.21%. 3. Study on the agronomic traits of the target lines in lower generations of 3 backcrossing combinations. Through this study, except several lines, the traits related to the yields all recovered or even surpassed the traits of recurrent parent, and the contents of oleic acid and linolenic acid are all stable through generations.