Abstract
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.
Highlights
Dendrobium is the general name of Dendrobium in Orchidaceae
1.1 Polymorphism analysis of primer amplification Six ISSR primers with clear amplification bands, high polymorphism and good repeatability were selected from 100 ISSR primers for PCR amplification (Figure 1)
The results showed that the genetic diversity of 22 species of Dendrobium was rich, and it was feasible to detect the genetic diversity of Dendrobium by ISSR molecular markers
Summary
Dendrobium is the general name of Dendrobium in Orchidaceae. There are about 2000 native species in the world and more than 80 native species in China (Wang et al, 2014). It has been found that molecular marker technology can effectively analyze the genetic diversity of Dendrobium and identify species quickly and accurately (Ren et al, 2015; Fu et al, 2017). ISSR (inter simple sequence repeat) is a molecular marker technique established by Zietkiewicz et al (1994) This technique has the advantages of simple primer design, low DNA consumption, high polymorphism, simple operation, rapid sensitivity and low experimental cost (Lu et al, 2013; Yang et al, 2019). It has been widely used in the study of genetic diversity, genetic relationship and genetic map construction
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