| In order to know more about the genetic diversity, genetic structure and genetic differentiation of Cymbidium faberi Rolfe populations, ISSR molecular markers were used to analysis the genetic diversity of C.faberi Rolfe mainly from Jiangxi Province and some correspongding conservation strategies were suggested. The study results could provide scientific guidance and basis for rational development and utilization of C. faberi Rolfe. The main results were as follows:The optimal ISSR-PCR reaction system and amplified procedures for C. faberi Rolfe were established by orthogonal design.25μl reaction volume contained2.5μl1*PCR buffer,2.5mmol/L Mg2+,120ng template DNA,200μmol/L dNTPs,0.75U Taq DNA polymerase,0.4μmol/L primer and15.35μl double distilled water. The optimal amplification procedures were pre-denaturing for5min at94℃, followed by40cycles of denaturing for45s at94℃, annealing for45s due to the temperature in terms of denaturing temperature of each primer, extension for80s at72℃. Then extension step of7min at72℃was performed and finally the products would be preserved at4℃.In this study,12ISSR primers were screened for the amplification of C. faberi Rolfe,142bands were resulted, of which129were polymorphic bands, and the percentage of polymorphic bands was90.85%. POPGENE analysis indicated that the genetic diversity of C. faberi Rolfe at the species level (PPF=90.85%, Hpop=0.2892, I=0.4393) and at the population level (PPF=59.40%, Hpop=0.1886,I=0.2865) were relatively high. Among the genetic diversity of all the population, the one of Nanfeng population (NF) was the highest (PPF=73.94%, Hpop=0.2498,I=0.3764) and the one of Guixi population (GX) was the lowest (PPF=45.77%, Hpop=0.1327,I=0.2053).Nei’s genetic distance (D) and genetic identity (I) were accounted by POPGENE. It indicated that the genetic distance (D) each other in17populations was in the range of0.0278to0.2476and the genetic identity (I) was the range of0.7807to0.9726in which the genetic distance (D=0.0278) between Guixi (GX) populations and Zixi (GX) populations was the smallest and the one (D=0.2476) between Xiushui (XS) populations and Shicheng (SC) populations. UPGMA cluster analysis of Nei’s genetic distance by NTSYS-pc of C. faberi Rolfe populations located in Jiangxi province showed that C. faberi Rolfe populations were divided into two pedigrees (pedigree I and pedigree II). Pedigree I was divided into two branches. Branch I included Guixi (GX), Zixi (ZX), Jing,an (JA), Lushan (LS) and Yushan (YS) population; Branch II included two groups, group I included Nanfeng (NF), Shaowu (SW) and Shicheng (SC) population; group II included Jinggangshan (JGS), Chongyi (CY), Huichang (HC) and Anfu (AF) population. Pedigree II included Xiushui (XS), Wuning (WN), Hengfeng (HF), Tonggu (TG) and Yifeng(YF) population.AMOVA analysis indicated that the genetic differentiation coefficient (Φst) among C. faberi Rolfe was0.3623, which showed that the genetic differentiation within population was greater than the one among populations. The genetic differentiation coefficients (Φst) among the populations respectively located in different mountains were as follows from small to large:Φst=0.189among three populations located in Luoxiao Mountains, Φst=0.313among six populations located in Wuyi Mountains,Φst=0.386among three populations located in Mufu Mountains, Φst=0.417among two populations located in Huaiyu Mountains,Φst=0.423among three populations located in Jiuling Mountains. It showed that the genetic differentiation among populations was weaker than the one within populations separately located in five Mountainswas. The results were the same as the ones analysised by POPGENE.Mantel statistics and analysis of genetic distance and geographical distance of seventeen C. faberi Rolfe populations was carried out by TFPGA and significance test was also carried out. The result(r=0.2399,p=0.0140>0.05) showed that correlation between geographical isolation and genetic differentiation was unobvious.In addition, some protection strategies for C. faberi Rolfe were suggested according to the its genetic diversity and genetic structure, such as protecting C. faberi Rolfe in its native environment, transplantating C. faberi Rolfe among populations, strengthening protection awareness. |
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