Association Analysis Of Phenotypic Traits With SSR And SCoT Molecular Markers In Dendranthema Morifolium (Ramat.) Tzvel.

Dendranthema morifolium(Dendranthema morifolium(Ramat.)Tzvel.)is perennial plant,which belongs to Asteraceae family and Dendranthema genus.D.morifolium germplasm resources are very rich,and the morphological diversification is easily affected by the environmental impact of its morphological variation which prevents classification of cultivars and genetic diversity researches.To study and understand the plant phenotypic traits is the basis of the research on plant taxonomy and genetic diversity.Association analysis is conducted with natural populations as the research object,in order to detect of marker loci and try to find the relevant analysis methods and quantitative trait loci linked.In this study,we selected 99 different of D.morifolium cultivars,measurement and analysis of the phenotypic traits combing with SSR(Simple Sequence Repeat)and SCoT(Start Codon Targeted Polymorphism)markers were used in order to find the associated and quantitative traits loci,and it will provide a large number of basic data for future chrysanthemum molecular marker assisted breeding.Through the research,we got the following results:We used high-throughput sequencing technology to develop SSR primers for D.morifolium.We obtained 32863 reads including 2251 SSRs,which were screened with MISA1.0 to search for sequences containing repeating units.SSR primers were designed using Primer5.0.To test the effectiveness of these SSR markers,we designed primers by randomly selecting 100 novel SSRs,and amplified them across 99 cultivars.Sixteen SSRs were polymorphic with the number of alleles ranging from 9 to 20(mean value was 11.187),and their expected and observed heterozygosity ranging from 0.4111 to 0.8896 and from 0.2418 to 0.8111,respectively.The polymorphism information content ranged from 0.409(JH 47)to 0.875(JH 41),average value was 0.767.These markers can be used for investigating genetic relationships of D.morifolium.The phenotypic variation coefficient analysis showed that variation of phenotypic traits among the varieties of D.morifolium varieties were greater than the variation within the species;and the variation within varieties were less than 0.200 variation among varieties were more than 0.200 individual variation among varieties of more than 0.600.Of the principal component analysis,were divided into 5 principal components and the rate of cumulative contribution was 77.417%,the first principal component in the middle of petiole length and leaf length traits in the contribution of the largest value in other principal components in plant height,inflorescence diameter,ray floret length and leaf width contribution value was larger.That floral traits and leaf morphological traits in classification study is very important for the study.Ten primers yielding clear and stable products were selected to process the 99 D.morifolium cultivars,generating 243 amplification bands,of which 240 were polymorphic.The percentage of polymorphism loci was 97.76%.Polymorphism Information Content(PIC)ranged from 0.849 to 0.961,with an average value of 0.930.SCoT markers thus appeared to effectively reflect the genetic diversity of D.morifolium cultivars.Through the genetic structure analysis showed that the selected cultivars were composed of 5 and 2 subpopulations,respectively.There were 8 SSR locis in the 16 SSR locis associated with 7 phenotypic characters(p < 0.01).Among which 3 traits of propagative organ(inflorescence diameter,inflorescence height,ligulate flower width)were associated with 5 loci,while 4 traits of vegetation organ(petiole length,leaf blade length,stipule size,lamina magnitude)were associated with 4 loci by using GLM models.Four phenotypic characters(inflorescence height,ligulate flower width,petiole length,leaf blade length)were associated with 3 SSR loci based on MLM models.Association analysis detected 21 SCoT marker loci corresponding to 7 phenotypic traits.In this study,we chosed different 99 D.morifolium varieties,through the detection of SSR and SCoT locis found associated with quantitative trait locis of D.morifolium.Through the study of association analysis,hope to speed up the breeding process of D.morifolium.