Evaluation Of The Main Fatty Acids Of The New-type Brassica Napus And Analysis Of The Associated Genetic Loci

There are eight major components of fatty acids in the seeds of the B.napus,palmitic acid(C16:0),stearic acid(C18:0),oleic acid(C18:1),linoleic acid(C18:2),linolenic acid(C18:3),arachidic acid(C20:0),eicosenoic acid(C20:1)and erucic acid(C22:1)respectively.The oleic acid,linoleic acid and linolenic acid which totally occupy 90% of the total fatty acids are the important compositions in the seeds of the low-erucic B.napus.The percent of the different fatty acids compositions in total fatty acids determines its nutritional value and commercial value.The lines with high oleic acid can be used as the breeding resource for high quality canola oil and biodiesel and the lines with high linoleic acid or linolenic acid can be used as the the raw materials for health products used to prevent and treat various diseases.It is rarely found that the oleic acid is more than 80.00% and the linoleic acids is more than 40.00% or the linolenic acid is more than 15.00% or the sum of the linoleic and linolenic acid is more than 50.00% in traditional B.napus.But the new germplasm resources with broaden genetic basis can be used for screening the materials with the special characters.In this study,we aimed to screening thounsands of lines for their fatty acids profile from the recurrent selection population,high generation inbred lines and the double haploid developed from a new-type B.napus population with the Cc subgenome of the B.carinata and the Ar subgenome of the B.rapa.We used the near infrared(NIR)and gas chromatograph(GC)to analyze the fatty acids compositions of the seeds,selected and purified the lines with high oleic acid(C18:1),linoleic acid(C18:2),linolenic acid(C18:3),constructed double haploid mapping population using the parents with derived trait of fatty acid,and analyzed the genetic associated loci with fatty acid in new-type B.napus.The results with details as following:1.To improve the effeciency of the GC analysis for new-type B.napus,a experiment was designed with three repeats using different number of the seeds for two cultivars of B.napus(Ningyou 7 and Tapidor)base on the improved method of extractting the fatty acids compositions in the seeds of the Arabidopsis thaliana.The results of the experiment proved that the 15 seeds could represent accurate result of the fatty acids compositions of the lines and save the seeds.2.We had got the high oleic acid materials and high linoleic acid,linolenic acid materials from the 3930 plant seeds of the recurrent selection population after 2-3 rounds of selection by NIRS,followed by GC analysis.The oleic acid contents of 10 F3 seeds is more than 75.00%,of which 2 are more than 80.00%,80.38% and 80.97% respectively.The oleic acid of the F4 seeds is not more than 75.00%.The sum of the linoleic acid and linolenic acid of 2 F3 seeds are more than 45%,45.45% and 49.25% respectively.The sum of the linoleic acid and linolenic acid of 34 F4 seeds are more than 45.00%,of which 12 are more than 50.00%,and the highest contents is 57.83%.3.The fatty acids compositions of 119 inbred lines seeds of the new-type B.napus were evaluated with three repeats by GC.The correlation among the eight fatty acids compositions were analyzed by the SPSS software.Genome-wide association analysis(GWAS)was carried out using 24877 SNP markers for fatty acids compositions of 119 inbred lines under four model(GLM,Q,K and MLM).The SNP significantly associated with oleic acid and erucic acid were identified.Two SNP associated with oleic acid were located on chromosomes A9 and C6,and the 15 SNP associated with erucic acid were on chromosomes A1?A2?A6?A9?C1 and C6.Two common SNP on chromosomes A9 and C6 were associated with oleic acid and erucic acid.4.In order to develop a DH population for further analysis of the genetic basis of fatty acid profiles of new-type B.napus,an inbred line at high generation with the highest content of high linoleic acid and linolenic acid(C18:2+C18:3?49.00%)elected from the above results,were crossed with two DH lines of new-type B.napus with relatively low linoleic acid and linolenic acid(C18:2+C18:3?28.00%).The F1 plants has been genotyped with SSR molecular makers for identify true hybrids.The flower buds of the true F1 plants were collected for microsproing cluture.Thousands of active embryo had been obtained for developing the DH mapping populations.