| Rapeseed is one of the most important oil crops in the world,and breeding for high oleic acid is one of the main objectives for quality improvements at present.In recent years,clubroot in rapeseed has spread rapidly,causing considerable yield losses and also affecting the cultivation of high oleic acid rapeseed in the inffected areas.Cultivating and planting disease-resistant varieties is the most cost-effective control method.Screening and identification of target genes through molecular marker-assisted selection(MAS)can accelerate the breeding of varieties and shorten the breeding period.This study aimed to introduce the club root resistant genes of CRb and PbBa8.1 into high oleic acid cultivars without the genes by MAS technique,and backcrossing to develop high oleic acid and disease resistant new cultivars.The major results are as follows:1.Identification of 14 resistant lines(HS5,ZS11 and SG 77)from different sources.Screening of BC2F2 population showed that the separation ratio of CRb sites was 1:2:1;After that,14 homozygous lines which contained high oleic acid and 3 lines of oleic acid sites were separated(the oleic acid separation ratio was 1:2:1).In the BC2F3 population,134 homozygous lines of CRb locus were identified,from these four lines with stable disease-resistantand high oleic acid(oleic acid content exceeded 75%)and 97 strains with high oleic acid content and excellent disease-resistant.Five strains contained PbBa8.1 resistance sites with 1:2:1 genotype separation ratio,were identified from the F4 population.2.The selected strains were identified for disease resistance in the disease plots in Huangshan and Jingmen.After that,eight strains with resistant,nine resistant isolates(4 isolates of disease-resistant genotypes were separated by 3:1)and 4 susceptible strains were obtained.3.The disease-resistant CRb and PbBa8.1 genes were separately introduced into elite lines with high oleic acid by hybridization.Twenty plants with homozygous resistance sites contained CRb and PbBa8.1.4.Gene analysis for disease-resistant,disease-resistant and high-oleic acid lines was performed,using the 6K SNP microarry of Brassica napus.The 3285 SNPs were mapped on the A01-C09 chromosome,and the average genome-wide density of SNPs was 196.17 kb/SNP and the average background recovery rates of H5(H5R),SG 77(SGR),YG 2009,and Z11 R were 88.93%,85.60%,88.70%,82.06%,91.10%,and 93.77%,respectively.PCA was applied to 110 disease-resistant contained high oleic acid materials and materials from four different background sources(HS5,YG2009,SG77,ZS11)were clustered together by material source.5.Fatty acids in leaves were analyzed with GC.The oleic acid content in the same lines of high oleic acid in the same growth perid of time was higher than that in the low oleic acid background.The content of linoleic acid and linolenic acid was just the opposite.Overall,the variaton range was much smaller than the ones of fatty acid content in the seed.The content of oleic acid in leaves is less than 3%,the content of linolenic acid is more than 30%(the lower the oleic acid content,the higher the content of linolenic acid)and the content of palmitic acid is more than 12%.The content of stearic acid and linoleic acid is close to that of seed,about 2% and 10% respectively.The low temperature will reduce the oleic acid content in some high oleic acid materials. |
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