Genetic Diversity And Classification Of Large-flowered Chrysanthemum With SRAP

Chrysanthemum×morifolium pertains to Chrysanthemum genus and Compositae family. On account of multitudinous cultivars and abundant morphological variation, classification and genetic diversity research of the cultivars became to be a great difficulty. Scientific classification and genetic diversity research were based on the precise analysis of Chrysanthemum traits. On the basis of DUS investigatation of large-flowered chrysanthemum in Chrysanthemum resource garden,85 representative large-flowered chrysanthemum are selected and their characters stability and variation are analysed from the morphological and molecular level. Furthermore,assiociation mapping of 58 large-flowered chrysanthemum's 18 quantitative characters is analysed by SRAP marker to search SRAP marker loci which are associated with quantitative characters, and analyse complicated characters. All of these result provide basic data to classification, research of genetic diversity and molecular breeding of large-flowered chrysanthemum. The main research results were as follows:1.Analysis of variation coefficient showed that there were 21 characters which show a high consistency within and specificity between cultivars observed in 57 chrysanthemum characters, thus these 21 characters are applied to classification and identification. R clustering analysis shows that plant height, number of tubal flower and ray flower are independent to other characters. Principle component analysis show that bigger Component value characters compose flower integrated character and leaf integrated character which are applied to classification appropriately.2. SRAP-PCR reaction system of Chrysanthemum morifolium is established and optimized. And 19 pairs of primers which are amplified strong and stable polymorphism are selected from 130 pairs of primers. SRAP amplification tests generate 283 bands, and 225 bands are polymorphic, so the average percentage of polymorphic bands is 80%. Polymorphism Information Content (PIC values) ranged between 0.64-0.92, and average value is 0.87. These indicated that the genetic diversity of Chrysanthemum is very abundant.3.UPGMA clustering analysis of SRAP showed that 50 chinese Large-flowered Chrysanthemum were divided into 4 groups, flat type group, tube type group, irregular type group and anemone type group. Spoon type groups dispersed clustering in the tube type and flat type group. That 8 japanese cultivars clustering together shows their geographical provenance is interrelated with the result of clustering analysis to a certain extent.4. Analysis of population structure shows 58 large-flowered chrysanthemum exits 5 subpopulations. This was consistent with SRAP UPGMA clustering analysis, and confirmed that SRAP UPGMA clustering analysis was feasible. Germplasm infiltration between Chinese cultivars and Japanese cultivars was found.5.There are 6 SRAP loci associated with 5 quantitative characters (P<0.01) in which ray flower correlative characters associated 5 loci, stem diameter and leaf thickness associated 1 locus respectively. The rate of expaination on the phenotype of related loci ranged between 0.0738-0.4791.Besides, there was "pleiotropic effects of one gene" and "a same result of several genes" phenomenon in association mapping.