| Brassica napus L is one of the most important oil crips with significant economic value in the world.Brassica napus L is believed to be rich in nutrition for Brassica napus L oil.On the other hand,due to the similiar component with diesel,oilseed is considered to be an important solution to the lack of petroleum.The 1000-seed weight of Brassica napus L was quantitative traits controlled by multi-gene and easily impact by envirnoment,which are difficult to be imporvement by tradition breeding method.It is possible to utilize marker assisted selection in Brassica napus L with the rapid development of molecular marker techniques.Nowdays,with the development of marker assisted selection,many breeder could improve Brassica napus L yield by genetic methodoloegies.In this study,we analyzed using SSR marker to preform genomic molecular marker scanning on the population.Our object was determine the genetic diversity,to identify their population structure.we combined the SSR genotype and 1000-seed weight phenotype in two years to detect by association analysis.Some novel alleles for each agronomic trait and their corresponding accessions were mined. To reveal the genetic diversity variation of Brassica napus L germplasm resources, has important significance to explore new germplasm or gene.The main results are as follows:1.The L9(34)orthogonal design was used to optimize the rape PCR reaction system which contained Mg2+,dNTP, primer and Taq enzyme four factors.Therefore using this four factors designs three levels to obtain optimal system.The result showed that the best optimal system was:10×buffer, 1.5mmol/LMg2+,0.1mmol/LdNTP,0.4mmol/Lprimers,0.05 UTaq enzyme,100ng/ul template,adding ddH20 to ensure total volume was 10 uL,PCR amplification was as follow: 94?(3min)then 1 cycle 94?(30s)60?(30s)72?(45s)then 8 cycles per cycle to reduce 0.5?,a total of 9 cyclest,then 36 cycles each 94?(30s) 57?(30s) 72?(45s) and aflnal extension at 72?for 10 min. The best optimal concentration of sliver staining was 0.1%. Establishing a set of effective system.2.171 material of Brassica napus L were evaluated for genetic diversity and cluser analysis using 108 SSR markers. The result showed that 108 SSR primer pairs amplified a total of307 alleles, 295(96.1%) were polymorphic. The values of the expected heterozygosity(He),polymorphism information content(PIC) and Shannon's information index(I) were 0.39, 0.67 and0.73,respectively.The values of He, PIC and I indicated the existence of high genetic diversity in the Brassica napus L'population. The Genetic similarity index was 0.755626,The 171 material were divided into three main groups by STRUCTURE cluster and UPGMA cluster. There are the highly accordance among two methods.3.Linkage disequilibrium values were calculated for 5780 pairwise comparisons among the108 SSR loci. Among all loci pairs, 638 pairwise comparisons(11.04%) were in LD at the P<0.05 level. The values of LD were all low with the range from 0 to 0.2.Among linked locus pairs,238(11.94% of 5780) pairs were in LD at the P<0.01 level.4.Association analysis was calculated by general linear model(GLM) based on 108 SSR loci and 1000-seed weight phenotype in two year in software TASSEL 2.0. Eighteen SSR loci were detected associated with 1000-seed weight at the P<0.05 level.For example,GR324?GR280?GR304?GR336 were repeatedly detected in two years.Then GR324?GR280?GR332?GR339 were detected significant associated with 1000-seed weight at the P<0.01 level.5.Allels of loci significantly associated with the traits were analyzed further to discover typical materials with effective allels for the traits. The result showed that the alleles GR280-152 had the maximum positive effect(+0.71g) and GR332-220 had the maximum negative effect(-0.43g).140 had three different postivite effective allels and 164 had two different postivite effective allels.138 had two different negative effective allels. |
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