| Herbaceous peony (Paeonia lactiflora Pall.) is an important herbal flower in China and its germplasm resources are very rich. In the long history of thousands of years of cultivation, subjecting to geographical constraints and changing climate, the group of herbaceous peony have produced a great deal of genetic variation and formed a rich genetic diversity on the basement of natural selection and artificial breeding. A large number of traditional cultivars and rare species were needed to be exploited and applied urgently. But with the development of modern agriculture and guidance of socio-economic, the germplasm resources of herbaceous peony are constantly being damaged or lost. Therefore, it is helpful to use the germplasm resources effectively by attaching importance to and carrying out collection and preservation of germplasm resources of herbaceous peony, and carrying on the research of genetic diversity of herbaceous peony simultaneously.In this research, with the objects of 150 cultivars of herbaceous peony germplasm and the main method of SRAP molecular marker, the genetic diversity of the resources was studied to reveal the genetic relationship between different species and their taxonomic status, and it could provide the basis for the future resources research,species identification,selection of breeding parents and exploration and utilize of excellent genetic resources; meanwhile, the core of herbaceous peony germplasm was initially built on this basis to manage resources effectively and make use of genetic diversity precisely. The main results were as follows:1. SRAP-PCR amplification experiment of herbaceous peony was established steadily. The reaction system was: 25μl of total reaction volume, including 2.5μl of 10×PCR buffer (100mmol·L-1 Tris-HCl pH8.3, 500 mmol·L-1 KCl), 2.5 mmol·L-1 of MgCl2, 0.25 mmol·L-1 of each dNTP, 0.3μmol·L-1 of each primer, 1U of rTaq, 120ng of DNA template. The reaction procedure was: denatured for 5 minutes at 95℃, the primer 5 reaction cycles were operated under the conditions of 94℃1min, 35℃1min, 72℃1min ;then, 40 cycles of annealing temperature is 50℃; at last, extended for 10min at 72℃, and preserved at 4℃.2. The genetic diversity of 150 herbaceous peony germplasm resources was studied with SRAP technology. After a double-selection in 120 primer pairs, 8 primer combinations were chosen to be used in the formal expansion, and 303 bands were produced, among which 286 were polymorphic bands, the polymorphism ratio was 94%, each primer combination produced 35.8 polymorphic bands. The number of polymorphic bands produced of every combination ranged from 24 to 44, and the polymorphism ratio of single primer combination was between 88.9% and 100%.3. By UPGMA cluster analysis, the genetic similarity coefficient of herbaceous peony ranged from 0.63 to 0.88. The result showed that all cultivars were divided into 5 major groups in the similarity coefficient of 0.66, The clustering result was very complex, but in-depth analysis carefully, it was found that each taxonomic group was be connected with geographic origin and color classification scheme,and it had general regulation and characteristic of color clustering on base of locality. It showed genetic diversity of geographical resources on Chinese herbaceous peony cultivars.4. The core germplasm resources of herbaceous peony was tried to be constructed. On the basis of regional groups, stratified cluster sampling was carried out by dominating molecular data and supplementing the traditional data such as phenotypic character. 5 groups of core germplasm was gained according to the sampling ratio 12%,16%,21 %,26% and 31%, and the diversity and practicality of the core ration was verified. According to laboratory data, the optimal core optimal was determined: 26% of the sampling ratio and 39 cultivars were selected as the core germplasm of herbaceous peony. Thus the theoretical foundation on molecular markers was established to protect and use herbaceous peony germplasm resources, at the same time, it was established the basis of further molecular marker-assisted breeding and important gene cloning.
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