Genetic Analysis And QTL Mapping Of Oleic And Linolenic Acid Content In Brassica Napus L.

High oleic and low linolenic content breeding is important for the quality breeding of Brassica napus resently. In order to find out the genetic mechanism of oleic and linolenic acid, in this study, linkage maps were constructed for mapping QTLs on fatty acid, protein content, oil content and glucosinolate content traits in 190 doubled haploid (DH) lines derived from the microspore culture of Fl whose parents were significant differents from the content of oleic and linolenic acid content. The major results were as follows:1. 190 of 386 DH lines whose parents were No.A254 which was high oleic(79.88%) and low linolenic(2.18%) and No.A177 which was low oleic(64.07%) and high linolenic(8.01%) were selected as the mapping population by random. A genetic linkage map, spanning 2330.8cM with an average 5.1cM, was constructed using 463 simple sequence repeat (SSR) markers. The common markers compared with the public maps information were according well with that in previous reports.2. In the DH population, 238 (46.03%) skewed from the expected 1:1 genotypic segregation by Chi-square test, and most of them centralized on N4, N13, N15, N19 linkage groups. The allele frequencies of No.A254 and No.A177 in all 517 loci were 47.66% and 52.34% respectively.3. With the data of napus quality traits collected from Wuhan in 2007 and 2008, 14 of 63 QTLs were detected in the two years in the DH population. For palmitic acid, 2of 6 QTLs were detected among the two years; 3 of 8 stearic acid QTLs were found in both years; 1 of 5 oleic QTLs was discovered in the two years; 2 of 4 linoleic QTLs were dectected twice; 3 of 7 linolenic QTLs were detected in the both years, and the two major effect QTLs were located on N4 and N14; 2 of 6 eicosenoic QTLs were detected twice; Both oil content and glucosinolate were detected 11 QTLs respectively, but none was detected in the both years.4. The main-effect QTL was located in the region of BNGMS265-BRGMS630 on N5, which could explain 84.63% of oleic variation. The DH population showed bimodal segregation of oleic, indicating the involvement of major gene for oleic and the environment had less or no effect on it. Also, we have mapped two loci that have major effects on low linolenic acid, one major QTL was located on N4 which could explain 59.0% phenotypic variation and the second major QTL resided on N14 which accounts for 23.52% phenotypic variation. In addition, the less effect QTL of linolenic which was located on N5 was a new QTL.5. We found that the correlation coefficient between high oleic low linolenic and the other quality traits is not significant, it suggests that, in our study, the special fatty acid component of high oleic and linolenic has no or less effect on agronomic traits and yield relatived traits.