Genetic Diversity And Phylogeographic Study Of Phyllostachys Chinensis In Jinfosha

Chimonobambusa utilis（Keng）Keng F,which is only distributed in the Daloushan Mountains,is an endemic species in southwest China.It is one of the main industries to shake off poverty and become rich in Tongzi and other counties due to its distinct flavor and delicious.A total of 20 natural populations were collected from the entire geographic distribution of C.utilis based on both the comprehensive field investigation and literature review in this study.EST-SSR molecular markers,chloroplast（cp DNA）and nuclear gene（ITS）molecular markers were used to study the genetic diversity and phylogeographic analysis of C.utilis populations.Based on the characteristics of haplotype distribution,it is inferred that there were at least two glacial refuge during the Quaternary Ice Age in C.utilis populations.This study is beneficial for further deepen our understanding of the complex mountain topography in southwest China and the effects of uplift of the Hengduan Mountains on genetic diversity,genetic structure and evolution of the species in the surrounding habitats.In addition,the relevant protection strategies and implementation methods of effective development and utilization in the later stage were put forward according to the degree of genetic differentiation and genetic differentiation among populations.The main research is as follows:（1）The genetic diversity of C.utilis populations was analyzed by using five pairs of EST-SSR molecular markers.The polymorphic information content（PIC）of the five pairs of primers was 0.732,all of which had high polymorphism.The observed alleles number（Na）and effective number of alleles（Ne）were 3.843 and 3.111,respectively.Compared with endangered species,the C.utilis populations has a higher level of genetic diversity.AMOVA analysis showed that the inbreeding coefficient of EST-SSR molecular markers was low（Fs _T=0.05021）,and the genetic variation was mainly come from within populations（94.98%）,and only 5.02%of the variation came from among populations.The results of Mantel test indicate that there was a very significant positive correlation between genetic distance and geographical distance,and no significant positive correlation between genetic distance and altitude gradient,indicating that the genetic variation among populations in C.utilis was mainly affected by geographical barriers.All populations of C.utilis populations were divided into three geographical unit by UPGMA cluster analysis,PCo A analysis and STRUCTURE cluster analysis,which could be divided into southern region,northern region and western region respectively.（2）There was no significant difference in genetic diversity between chloroplast markers and nuclear markers（cp DNA:H_T=0.956,Hs=0.507;ITS:H_T=0.868,Hs=0.495）.There are great differences in genetic diversity among different populations of C.utilis populations.According to the geographical distribution map,the haplotype polymorphism and nucleotide polymorphism values of MB population,DSH population in the north of Daloushan Mountains and JS population,GL population and CS population in the southwest of Daloushan Mountains are higher.Therefore,it is speculated that there may be two or more glacial refuge during the Quaternary Ice Age in C.utilis populations.AMOVA analysis showed that the genetic variation of the two molecular markers was mainly from among populations of C.utilis,and the genetic differentiation coefficient(F_ST)was high(cp DNA:F_ST=0.84135;ITS:F_ST=0.70121).Based on the cp DNA and ITS sequence detection and analysis of the historical dynamics and neutral test of the C.utilis population,the results show that the population has experienced a rapid expansion in the near future.（3）In order to reasonably and effectively develop and utilize the natural population of C.utilis,according to the genetic diversity and differentiation among populations,the population can be divided into 2 evolutionary units and 3 clades.the protection and management measures of both conservation in situ and conservation ex situ are put forward.