| The Prunus subgenus cerasus belongs to the family Rosaceae. It includes manys of species, most of which distribute in the north temperate zone. It is a kind of plants and have high economic value which destroyed badly by disaster and people. To better protect and make use of these gennplasm resources, this paper has for the first time performed molecular phylogeographical researches using PCR-RFLP technique on the basis of large-scale collecting of plant materials of Subgenus cerasus.Firstly, by visiting specialists, looking up related literature and referring to specimens, and through field surveys in 25 representative sites across 11 provinces and cities, this paper has for the first time given a relatively comprehensive and timely report about Subgenus cerasus. 's situation such as its growth status, habitats and artificial disturbances. All these have provided fundamental materials for the performing of related comprehensive researches. It reveals that Yunnan, Sichuan,Guizhou, Hubei, Shaanxi are primary producing areas of wild Subgenus cerasus. The wild resources are rich and widely. Gardens, departments and scientific research institutions propagandize little, so people know little about the resources, and young trees are indulged to live and destroyed by people. The resources are not made full use of, cultivating excellent breeds is trailed production need. Production areas are short of scientific supervision and high-tech is popularized difficultly.Secondly, relationship among Subgenus cerasus. including 10 species is studied. Phylogeny tree showed species segregation of wild Subgenus cerasus. in Chinese. Prunus stipulacea was closely related to Prunus. Tomentosa Prunus cl- arofolia, Prunus conradinae and Prunus discadenia's genetic relationship was also close. Prunus japonica, Prunus serrul, Prunus polytricha, Prunus serrulata and Prunus pseudocerasus had close phylogenetic relationship with them. There was a absent gene intercourse, distinct genetic differentiation and generative segregation. Subgenus cerasus. had a differentiation a long time ago. Prunus pseudocerasus, Prunus polytricha, Prunus japonica, Prunus serrul and Prunus serrulata are primordial;Prunus stipulacea, Prunus discadenia, Prunus conradinae and Prunus clarofolia are evolutional.Thirdly, 21 cpDNA haplotypes are detected through the analysis of all the fragments of Subgenus cerasus. by using 42 primer/enzyme combinations. Genetic distances and clustering relationship detected that Prunus pseudocerasus earning from Yunnan, Sichuan and Guizhou are the most primordial haplotypeAccording to haplotypes' cpDNA genetic diversity in Prunus. Tomentosa, Prunus clarofolia, Prunus pseudocerasus, Prunus polytricha, Prunus serrulata is 0.0340, 0.0217, 0.1400, 0.0166,0.0192 respectively.According to haplotypes' pattern of geographical distribution and inhabiting ranges, the investigated Subgenus cerasus. populations can be divided into 20 geographical units. Genetic differentiation of cytoplasmic genome was analyzed by PCR-RFLP technique. Variation coefficient (Gst) of Prunus. Tomentosa, Prunus clarofolia prunus pseudocerasus, Prunus polytricha, Prunus serrulata among geographical units is 0.7934> 0.3730, 0.3630> 0.7928> 0.6092 respectively, indicating that most of the genetic variation exists among the geographical distribution unitswith regard to Prunus. Tomentosa, Prunuspolytricha, Prunus serrulata, and there was considerable genetic variation exists among the geographical distribution units with regard to Prunus clarofolia and Prunus pseudocerasus,.Which indicating a remarkably significant level of genetic differentiation among geographical unit The calculation based on Gst value shows that the cpDNA gene flow among geographical units is 0.1302, 0.8405> 0.8773> 0.1307, 0.3207 respectivelys. Near distance transmitting of fruits and seeds, Perennial mountain obstruct of geographical units lead a low level gene flow among geographical units.Results of AMOVA analysis show that Prunus Tomentosa, Prunus clarofolia, Prunus pseudocerasus's genetic differentiation within populations is 0.097%, 0.0739%, 0.7071%, Prunus polytricha and Prunus serrulata have no genetic differentiation within populations.respectively, indicating that most genetic differentiation exists among the populations again, and genetic differentiation of Prunus polytricha and Prunus serrulata exists among the populations completely. Lacking gene flow was proved ulteriorly.Results of Mantle correlation analysis between interpopulational geographical distances and interpopulational genetic distances show no significant positive correlation in Prunus Tomentosa, Prunus clarofolia and Prunus pseudocerasus, but a remarkably one in Prunus serrulata (P<0.01). r=0.7339. Genetic differentiation between interpopulational in Prunus serrulata is remarkabal. Lacking gene flow was proved ulteriorly and Genetic differentiation between interpopulational in Prunus serrulata was generated remarkablely.Fourthly, according to the haplotypes, the area of Yunnan, Guizhou, Sichuan is origin and evolution center of Subgenus cerasus., and Qinling's south slope, Dabashan's east section is secondary centres of origin and evolution center. There are many of haplotypes which take a large portion of all haplotypes in, there are haplotype 3,4,5,6,9,12,14,16,17,18 and 20, for it is the center of diversity.Based on the distributing pattern of haplotypes it conferred that Subgenus cerasus. transferred to others areas after origining from Yunnan, Guizhou, Sichuan along many routes. When the glacier of Quaternary period came, Subgenus cerasus. plants migrated southwards and inhabited 6 refugia including Yunnan, Qingliangfeng Mountains, Qinling's south slope and Dabashan's east section, Fanjingshan Mountains, Beijing, Shandong Province.After the end of glacial age, haplotype 8 fromYunnan Province migrated northeast along the the Changjiang River to Huangshan Mountains, Qingliangfeng Mountains, Lushan Mountains, and haplotype 13 migrated west to Minshan Mountains, and the other north to Qinling's south slope. Haplotype 21 from Qingliangfeng Mountains migrated to Huangshan Mountains and Lushan Mountains. Haplotypes 3 and 18 from Qinling's south slope and Dabashan's east section migrated west to Minshan Mountains. Haplotype 9 from Fanjingshan Mountains migrated to Hupingshan Mountains unto Dabashan's east section along Wulingshan Mountains. Haplotype 20 from Taishan Mountain migrated to Benxi, and haplotype 2 from Beijing migrate to Dalian, and the current distribution pattern was eventually formed.Fifthly, based upon the above-mentioned results, several suggestions about the preservation and utilization of Subgenus cerasus. plants have been proposed: (1) Propagandize indigenous wild resource in china. (2) it should be forbidden to cut down parental trees or damage seedlings. (3) Lead the large populations distributing small areas and single survival environment to other fitting environment;Prevent the small populations distributing large areas and single survival environment to decay. (4) Check existent resources, establish species resources gardens and excellent gene banks, breed excellent species. (5) Electting primordial survival species on the corresponding ecosystem condition to apply to gene resources, evolutional ones' special character for production is expected to obtain new species with independent property right. (6) Popularize high-tech of fruit trees. Breeding technology of Subgenus cerasus. should be researched deeply and practical problems in large-scale production should be resolved.Lastly, the research that follows should pay more attention to demonstrate genetic relationship among species, intraspecific genetic diversity and pattern of genetic differentiation of Subgenus cerasus. by means of AFLP molecular markers. Contrasting result of this paper by PCR-RFLP and through Mantel detection, the identity of the results obtained from AFLP and PCR-RFLP analysis respectively should be analyzed.
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