| Chinese cherry generally refers to species Prunus pseudocerasus Lindl. (Cerasus pseudocerasus (Lindl.) G.Don),belong to Rosaceae, and is originated from China and wide distributed in China. Local Chinese cherry varieties contaions the rich Chinese Cherry germplasm and have the widest geographic distribution. Due to the small fruit and poor transportation, Chinese cherry do not getting the attention they deserve. People neglecting to highlight its individual traits and even some of the best comprehensive properties of the local germplasm. Sweet Cherry varieties (Cerasus avium) mass into the Chinese market, accelerate the speed of damage and loss of Chinese cherry germplasm.In order to effectively preserve and utilize these germplasms, genetic diversity and population genetic structure among 18 populations (total 154 individuals) based on ITS sequence were analyzed. The main results were as follows:1. Genetic diversity of local Chinese cherry varietiesThe results showed that 11 haplotypes were yielded based on the alignment of 154 ITS fragment. (1) The haploid type H1 are distributed in all groups and is the most widespread and the main type of all the groups. (2) In all 18 groups, the ITS sequence of haploid type diversity (h) and nucleotide diversity (π) of the test results show that the cultivation of Chinese cherry germplasm showed a low. level of genetic diversity (h= 0.5590, π= 0.0012), and a single genetic diversity level showed a larger difference between groups (h = 0-0.9050,π= 0-0.0061).2. Population genetic structure among local Chinese cherry varieties(1)By using the SAMOVA genetic variation for all groups, the analysis results show that when K= 3 when detected the greatest FCT has grown and the greatest population differences (FCT= 0.3072, P= 0.0029), showed that all groups can be divided into three groups, guizhou bijie (BJ) groups and groups from guizhou guiyang (GY) be divided as a group, and groups from other places become another group. (2)The results of AMOVA showed that the genetic differentiation between 18 groups is not obvious (FST= 0.1400, P = 0.0000), most of the genetic variation mainly distribution within the group (86%). SAMOVA grouping analysis showed a similar genetic differentiation.(3)The analysis between populations genetic differentiation shows that the genetic differentiation between the two groups coefficient of Fst showed great changes. Based on K-2p genetic distance of N-J group clustering result shows that 18 groups can be divided into three branches.(4)For all groups of neutral inspection results showed that all groups of Tajima’s D value is significantly negative (Tajima1 s D= 1.7790, P< 0.05);And Fu and Li’s D*=-1.8098 (P> 0.10) and Fu and Li’ s F*=-2.1558 (0.05<P< 0.10) were negative, but not exist significant statistical tests. Groups of mismatch distribution analysis showed that Chinese cherry may experienced a recent population expansion.These results suggested that founder effect and bottleneck effect produced by domestication and recent reduction of population strongly affected the genetic diversity. The long alternation of generation and shorter history of differentiation may led to a low genetic differentiation among populations. According to these findings, further strategies and suggestions for conservation of these resources were also proposed. |
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