| In present study, ISSR molecular markers were used to analysis the genetic diversity of a total of 390 individuals of Cymbdiium goeringii, of which 350 from Jiangxi province.20 from Wuyishan in Fujian province and 20 from Shaowu in Fujian province. The aim was to comprehend the genetic diversity and genetic structure of C. goeringii populations and the genetic differentiation among the populations. It was also to provide theoretical proof for protecting and utilizing C. goeringii. The main results are as follows.The optimal ISSR-PCR reaction system and amplified procedures for C. goeringii were established.25μl reaction volume contained 1* PCR buffer,2.0 mmol/L MgCl2,100 ng template DNA,200μmol/L dNTP,1.4 U Taq DNA polymerase and 0.4μmol/L primer. The optimal amplification procedures were pre-denaturing for 5 min at 94℃, followed by 40 cycles of denaturing for 45 s at 94℃, annealing for 45 s, extension for 80 s at 72℃. Then extension step of 7 min at 72℃was performed.In this study,14 ISSR primers were screened for the amplification of C. goeringii,139 bands were resulted, of which 118 were polymorphic bands, and the percentage of polymorphic bands was 84.89%.POPGENE analysis indicated that the genetic diversity of C. goeringii. was higher compared to other species:at the species level (PPF= 38.30%, Na=1.3830, Ne= 1.2063, Hpop=0.1219, I= 0.1851) and at the population level (PPF= 84.89%, Na= 1.9065, Ne=1.3687, Hpop=0.2292,I=0.3613). Among the genetic diversity of all the population, the one of Guixi population (GX) was the highest (Hpop=0.1649) and the one of Jinggangshan population (JGS) was the lowest (Hpop=0.1649).WINAMOVA analysis indicated that the high level of genetic differentiation was existed among C. goeringii populations and the genetic differentiation coefficient (ΦST) was 0.4425, which showed that the genetic differentiation within population was smilar with the one among populations. The genetic differentiation coefficients (ΦST) among the populations respectively located in different mountains were as follows from large to small:ΦST= 0.5842 among four populations located in Luoxiao Mountains,ΦST=0.5439 among four populations located in Dayuling and Jiulian Mountains,ΦST=0.4815 among three populations located in Jiuling Mountains,ΦST =0.4496 among five populations located in a section of Mufu Mountains and Jiuling Mountains,ΦST=0.4363 among six populations located in Wuyi Mountains,ΦST= 0.2916 between two populations located in Mufu Mountains,ΦST=0.1383 between two populations located in Huaiyu Mountains.It showed that the genetic differentiation within population separately located in Huaiyu Mountains, Mufu Mountains, Wuyi Mountains, Jiuling Mountains, and a section of Mufu Mountains and Jiuling Mountains was higher than the one among populations and the genetic differentiation among populations separately located in Dayuling and Jiulian Mountains and Luoxiao Mountains was higher than the one within population.Nei's genetic distance (D) and genetic identity (I) were accounted by POPGENE. It indicated that the genetic identity (I) each other in 21 populations was in the range of 0.0320 to 0.2971 and the genetic distance (D) was the range of 0.0320 to 0.2971 in which the genetic distance (D=0.0320) between Yushan (YS) populations and Hengfeng (HF) populations was the smallest and the one (D= 0.2971) between Anfu (AF) populations and Dayu (DY) populations. UPGMA cluster analysis of Nei's genetic distance by NTSYS-pc and principal component analysis (PCA) of C. goeringii populations located in Jiangxi province by MVSP showed that C. goeringii populations were divided into two pedigrees (pedigreeⅠand pedigree II). Pedigree I was divided into two branches and branch I included three groups, group I included Yushan (YS) population and Hengfeng (HF) population; group II included Xiushui (XS) population, Wuning (WN) population and Tonggu (TG) population; group III included Guixi (GX) population and Lichuan (LC) population, and then group I and groupⅡclustered. BranchⅡincluded two groups, groupⅠincluded Xunwu (XW) population, Dayu (DY) population and Chongyi (CY) population; groupⅡincluded Anyuan (AY) population, Jinggangshan (JGS) population, Lianhua (LH) population, Jing'an (JA) population and Longnan (LN) population. PedigreeⅡwas divided into three branches, branchⅠincluded Wuyishan (WYS) population and Yifeng (YF); branchⅡincluded Zixi (ZX) population and Shicheng (SC) population, branchⅢincluded Shaowu (SW) population and Anfu (AF) population, and then branchⅠand branchⅡclustered.Mantel statistics and analysis of genetic distance and geographical distance of twenty-one C. goeringii populations was carried out by TFPGA and significance test was also carried out. The result was that negative correlation was presented between genetic distance and geographical distance, which showed that genetic differentiation correlation of geographical isolation at a high level was unobvious.Some conservation strategies were suggested according to above-mentioned result. Genetic diversity of Yifeng (YF) population was relatively high and the resource was relatively severely destroyed and the resources of Anfu (AF), Jing'an (JA), Lianhua (LH) and Jinggangshan (JGS) were relatively abundant and genetic basis was relatively week, so conservation regions or spots were suggested to be established in these districts in order to conserve the habitat and promote the seedlings to regenerate and the wild populations to renew. The habitats of Anyuan (AY) poulation, Xunwu (XW) population, Chongyi (CY) population, Longnan (LN) population and Dayu population were severely destroyed, and translocation conservation was the only feasible protection strategy, in addition, pedigree diversity and population specificity must be considered when translocation conservation was carrying out, meanwhile the possible outbreeding depression among pedigrees should be also considered. |
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