Genetic Diversity Analysis and DNA Fingerprint Construction of Dendrobium Based on ISSR Markers

In order to make reasonable use of collected and preserved  Dendrobium  germplasm resources, ISSR molecular marker method was used to analyze the genetic relationship and genetic diversity of 22  Dendrobium  species. A total of 6 primers with clear amplification bands, high polymorphism and good repeatability were chosen from 100 ISSR primers. The selected primers were used to amplify the genomic DNA of 22  Dendrobium  species by PCR, and a total of 241 bands were generated, of which 241 were polymorphic bands. Polymorphic ratio was 100%. By GenAlEx 6.5 software, average value of observed allele number, effective number of alleles, Nei's gene diversity and Shannon's information index was 1.983, 1.167, 0.133 and 0.247, respectively, indicating that a high level of genetic diversity among 22  Dendrobium  species. The genetic similarity coefficient among 22  Dendrobium  species ranged from 0.698 4 to 0.878 7 by NTSYS-pc 2.1 software. UPGMA clustering based on genetic similarity coefficient, 22  Dendrobium  species could be divided into 10 groups when genetic similarity was 0.795. UPGMA clustering results are consistent with traditional morphological classification results. The DNA fingerprint map constructed with 3 pairs of primers can separately identify 22  Dendrobium  species. This research laid a theoretical foundation for the identification of  Dendrobium  germplasm resources and the selection of parents for cross breeding.