| In this research, peony germplasm which originate from China are choosen as the experimental materials (including 257 cultivars and 4 wild species) for 2-year measurement on phenotypic traits, meanwhile, combining with previous research results,29 markers with high polymorphism which are suitable for the study are selected, then successfully gain the genotype datas of these 261 peony germplasm, and 257 cultivars’ molecular identity cards are built, nextly genetic diversity of these germplasm are analyzed, afterwards the population structure and linkage disequilibrium are concerned, thus association analysis on markers/traits are carried out, what’s more, the study discuss the site significantly related to ornamental traits and calculate the sites’ interpretation rate on traits, so as to provide the reference for cultivars’ identification and improve the ornamental traits by molecular marker-assisted breeding. Main conclusions are as follows:(1) The study choses 12 peony cultivars which have long cultivation history as materials, uses SSR molecular marker technology and combines 6% none-denaturing polyacrylamide gel electrophoresis and quadruple fluorescence capillary electrophoresis, thus 29 pairs of primes with strong stability and high polymorphism are selected from 111 ones.(2) 29 pairs of primers with high polymorphism are applied in 257 cultivars and have got well amplification. The result shows:the ranges of PIC are 0.19～0.85, with an average of 0.59 (>0.50). Then the research constructs molecular identification of every cultivar by combining numbers and letters with ranking.(3) The 29 pairs of primers are used to analyze the genetic diversity of 261 peony germplasm. The results show that there are totally 272 alleles by 29 SSR primers, each pair is 9.38 on average; there are totally 620 polymorphic bands are amplified, each pair has 3～51 ones, each marker has 3～51 polymorphic bands, the length of amplification fragment is 91-419. The cluster analysis using UPGMA method shows that 261 peony germplasm resources are classified as 2 groups. The group I include 4 wild species,257 cultivars are fallen into group Γ, they can be classified into 8 categories. It indicates that the SSR markers is a good reflection of the rich germplasm diversity information, they can be used in the character correlation analysis.(4) By analyzing population structure of these 257 cultivars, the colony can be divided into 3 subsets; besides,29 pairs of SSR markers form 406 combination locus, mostly concentrated in 0.1-0.2, it fairly shows the linkage disequilibrium. Combining with the section analysis above, it’s certain that the group which is composed of 257 cultivars is suitable for correlation analysis between ornamental characteristics and the molecular markers.(5) On the basis of analying genetic diversity and colony structure of 257 peony cultivars and the degree of linkage disequilibrium between 29 SSR loci,the research conducts the correlation analysis between ornamental characteristics and the molecular markers by GLM and MLM models through TASSEL 4.3 software. The result shows:On the one hand, based on the GLM model analysis,23 markers are associated with 8 qualitative character at P<0.05 level, among which 12 are associated with 6 traits at a significant level (P<0.01); 4 markers are associated with 3 quantitative character in P<0.05. The interpretation rate of the markers on the phenotypic variation are between 0.2755 and 0.0317. On the other hand, based on the MLM model analysis,13 markers are associated with 7 qualitative character in P<0.05, Less than 10 compared with GLM model, but only Knu 39 is related to flower color at the P<0.01 level. The variation range of interpretation rate is 0.0195-0.1194, lower than the results analysied by GLM model. |
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