| Cymbidium goeringii belongs to genus Cymbidium, family Orchidaceae, which are the perennial herbaceous plant, also are state rare and endangered protected plant. However, Because of the increasing of orchids market and the drive of interests, some persons excessively digged wild orchid resources, which led to the natural habitats and wild resources of Orchids forced to the severe damage. Jiangxi province is located in the east China mainland, also is a core area of Chinese flora, which of China.Jiangxi has rich resources of orchids. Especially the C. goeringii and C. ensifolium were rather abundant, because they are easier to be found and to be digged, those wild orchid resources are easier to be destructed and deteriorated, how to strengthen the protection and sustainable utilization will be imminent. By DNA ITS molecular marker, we analyzed and compared the genetic structure, genetic diversity, genetic differentiation and gene flow characteristics of different geographical population of C.goeringii in the Jiangxi province, from the perspective of conservation genetics to indicate endangered factors of Jiangxi C. goeringii, at the same time, it will be the Scientific basis of conservation and sustainable utilization of wild C. goeringii resources, which the main results are as follows:(1)100individuals of11different C. goeringii populations in Jiangxi province were collected and tested. The mitochondrial ITS fragments were amplified and sequenced from all samples. As a result,13different haplotypes were detected, of which11were shared haplotypes from75%individuals. The aligned consensus ITS fragment was699bases long. The number of variable sites was29, which accounted for4.15%of the total sites. Among the100ITS sequences, the overall nucleotide diversity (pi) was0.413%, and haplotype diversity (TD) was0.489. In each population, the haplotype diversity from0.000to0.857and the nucleotide diversity ranged from0.000%to1.567%. In general, the genetic diversity was existed in all sampled populations.(2) The analysis of haplotype network revealed three well-supported clades:the A clade included eleven populations with thirteen haplotypes belonging to89individuals; the B clade contained three populations with three haplotypes of six individuals; the C clade represented only lpopulations with two haplotypes from four individuals. The distribution of haplotypes in the haplotype network did not show clear correlation with geographical distribution. The Bayesian and MP consensus trees showed two clades with the same topological structure and haplotype composition as revealed by the haplotype network. Moreover, in the Bayesian and NJ trees based on individuals, individuals from two different geographical populations were mixed together without a clear geographical pattern. The results of haplotype network and phylogenetic trees indicated that there was no obvious phylogeographic structure for C. goeringii.(3) AMOVA results showed eleven geography in the study population as a large group, genetic variation between accounted for40.02%of the total variability, genetic variation within accounted for59.48%of the total variability (FST=0.40). Overall, population and among populations, there are no significant genetic differentiation. These results suggested that, for C. goeringii, genetic differentiation occurred among individuals, and most of the genetic differentiation occurred within populations. But for most of the population, the genetic distance between each other are small. |
PDF Full Text Request