目的 探讨不同地区金钗石斛Dendrobium nobile居群间的遗传多样性及遗传分化关系。方法 基于引物结合位点间扩增（inter-primer binding site，iPBS）分子标记对广西5个县共35份金钗石斛进行遗传关系、遗传多样性和种群间遗传分化分析，并构建能区分35份金钗石斛种质的DNA指纹图谱。数据分析使用NTSYS-pc 2.10e统计软件计算遗传相似系数并构建聚类分析图谱，采用Popgene 1.32软件计算遗传多样性指数与居群遗传分化系数。结果 8条iPBS引物共扩增出158条条带，多态性条带为143条，多态条带百分率（percentage of polymorphic bands，PPB）为90.51%；在遗传距离0.70处，35份种质分为7大类群，居群在分子水平上出现明显分化；遗传相似系数（genetic similarity coefficient，Gs）变化范围为0.559 0～0.975 9，变幅为0.416 9；平均观测等位基因数（observed number of alleles，Na）、平均有效等位基因数（effective number of alleles，Ne）、Nei’s基因多样性指数（Nei’s gene diversity index，He）、Shannon多样性信息指数（Shannon information index，I）分别为1.898 7、1.505 0、0.300 7、0.454 2，居群间存在丰富遗传多样性；基因多样度（total genetic diversity，Ht）、各居群基因分化系数（gene diversity within population，Hs）、居群间遗传分化系数（coefficient of gene differentiation，Gst）分别为0.299 8、0.214 9、0.283 0，居群间遗传变异占总变异的28.30%，居群内的遗传变异占总变异的71.70%，遗传变异主要来源于居群内部；基因流（gene flow，Nm）为1.266 5，居群间存在较高水平的基因交流。引物2219和2399可单独鉴别出35份种质，试验基于引物2399的“0，1”矩阵构建35份种质的指纹图谱，此图谱可为金钗石斛品种的分类与鉴定提供参考。结论 金钗石斛居群间遗传多样性较丰富，总变异主要来源于居群内变异，居群间存在较高水平的基因交流。揭示了金钗石斛种质间的遗传关系及其居群遗传多样性，为野生金钗石斛种质的保护工作的开展奠定基础。
Objective To explore the relationship between genetic diversity and genetic differentiation among populations of Dendrobium nobile in different regions. Methods Inter-primer binding site (iPBS) molecular markers were used to analyze the genetic relationship, genetic diversity and genetic differentiation among populations of 35 D. nobile from five counties in Guangxi, and construction of DNA fingerprints that can distinguish 35 germplasms. Data analysis used the NTSYS-pc 2.10e statistical software to calculate the genetic similarity coefficient of D. nobile and construct the cluster analysis fingerprint, the genetic diversity index and population genetic differentiation coefficient were calculated with Popgene 1.32 software. Results Eight primers were used for PCR amplification of 35 germplasms, the results showed that a total of 158 bands were amplified by eight primers, of which 143 were polymorphic, and the percentage of polymorphic bands (PPB) was 90.51%. At the genetic distance of 0.70, 35 Dendrobium nobile germplasms could be divided into seven groups, and five populations showed obvious differentiation at the molecular level. The genetic similarity coefficient (Gs) ranged from 0.559 0 to 0.975 9 with the variable amplitude of 0.416 9. The results showed that the average observed number of alleles (Na) was 1.898 7, the average effective number of alleles (Ne) was 1.505 0, the Nei's gene diversity index (He) was 0.300 7, and Shannon information index (I) was 0.454 2. It indicated that there was abundant genetic diversity among populations of Dendrobium nobile. Total gene diversity (Ht) was 0.299 8, gene diversity within population (Hs) was 0.214 9, and the coefficient of gene differentiation(Gst) was 0.283 0. The inter-population genetic variation accounted for 28.30% of the total variation, and the intra-population genetic variation accounted for 71.70% of the total variation, it showed that the genetic variation mainly came from within the population. The gene flow (Nm) among populations was 1.266 5, indicating that there was frequent gene exchange among populations. Research was found that primers 2219 and 2399 could identify 35 germplasms separately. In this study, DNA fingerprints of 35 germplasms were constructed based on the "0, 1" matrix of primer 2399, This DNA fingerprint can provide a reference for the classification and identification of D. nobile varieties. Conclusion Genetic diversity among populations of D. nobile was rich, total variation was mainly derived from intra-population variation, and there was a high level of gene exchange among populations. The results revealed the genetic relationship and population genetic diversity among D. nobile germplasms, which laid a foundation for the protection of wild D. nobile germplasm.