Genetic Diversity Of Castanopsis Kawakamii Populations

Castanopsis Kawakamii is at the risk of becoming extinct in the wild,which has been classified as national key protected plants.It particularly distributes in the southern margin of the subtropical region in China.Due to human disturbance and natural factors,C.Kawakamii resources have been highly endangered.The biological factors including genetic structure,genetic variation and genetic evolution may be the main reseaon which influences C.Kawakamii populations in danger.Therefore,We used ISSR markers to detect the genetic diversity of C.Kawakamii population.The main results were summarized as follows.（1）Using the improved CTAB method,high purity DNA was obtained from C.Kawakamii leaves,and the DNA extracted by this method had higher yield,better quality,and could be used for ISSR-PCR reaction.（2）Optimize the ISSR-PCR system of C.Kawakamii,and several clear and stable bands with polymorphism were obtained.Based on the common ISSR-PCR reaction program and adjusting experiments,the optimal amplification program was described as follows:94℃for 5min;34 cycles at 94℃for 30 s,52℃for 45s and 72℃for 1.5 min;72℃for 10 min at last.PCR system（20μL total volume）contains:Template DNA 20 ng,dNTP 0.10 mmol/L,10×PCR Buffer2.0μL,Primer0.2μmol/L,Taq DNA Poltmerase0.75 U,ddH₂O11.7μL,MgCl₂2.0 mM.（3）ISSR analysis of C.Kawakamii resources.51 C.Kawakamii varieties were analyzed by ISSR with 10 random primers.A total of 113 DNA bands were amplified,among which 98 bands（86.73%）were polymorphic.The results showed that high genetic diversity among C.Kawakamii varieties.Genetic similarity among C.Kawakamii were obtained by SPSS13.0,Calculate the similarity coefficient between samples to establish genetic relationship dendrogram.According to GD = 0.19 in the gendrogram,74 materials were assigned to two populations.The first group included 43 copies of materials,mainly for Nanping,Sanming,and Jiangxi populations;the second group included 8 copies of materials,mainly for Longyan and Jianning populations;the third group included 23 copies of materials,mainly for guangdong and guangxi. Visible Castanopsis populations and their molecular structure consistent pattern of geographical space, there is a significant positive correlation. Because of geographical proximity, similar climate types, gene flow more likely, and therefore smaller genetic distance; the other hand the geographical distance, the larger changes in ecological factors,C.kawakamii the pressure of natural selection is different than in the evolution of form Large genetic distance. Cluster analysis and geographic distribution of natural consistent survey wild populations can be combined with molecular markers to assess genetic diversity in Subtropical price,to further explore the genetic C.kawakamii geography and population genetic structure of temporal variation.（4）POPGENE analysis showed that C.kawakamii populations rich in genetic diversity levels（Percentage of polymorphic PPB = 86.73%, Nei’s gene diversity H = 0.2791, Shannon’s information index I = 0.4246）.Total genetic variation present in 46.23% in population,the genetic variation within populations was 53.77%,Table Minge among populations in Subtropical and compared within populations there significant genetic differentiation. UPGMA cluster analysis shows C.kawakamii genetic distance and geographical distance was positively correlated. Based on C.kawakamii study population genetics and ecology of the results,should increase the genetic diversity of populations of C.kawakamii high protection,and strengthen the various groups of individuals within each seedling transplanting transplanting and seed production and promote population of gene flow, genetic diversity to maintain a balance of various groups in order to maximize the resources saved C.kawakamii genetic diversity.