Analysis of the Germplasm Resources and Genetic Relationships Among Hybrid Cymbidium Cultivars and Native Species with RAPD Markers

The random amplified polymorphic DNA (RAPD) marker was assessed to detect the genetic relationships among 48 hybrid Cymbidium cultivars from Japan, Korea, China, and USA, and 2 species of native Cymbidium. Twenty primers were screened from 100 random decamer primers, and a total of 258 DNA bands were amplified, 253 of which (98.1%) were polymorphic. The average number of polymorphic DNA bands amplified by each primer was 12.6. All cultivars were distinguishable when a number of primers were considered. Genetic similarities among the cultivars and species were estimated based on the amount of band sharing ranging from 0.364-0.817 with an average of 0.581. According to the data, a dendrogram of genetic relationship, which was constructed using the UPGMA method, showed that all the tested cultivars and native species were classified into five cluster groups with the similarity coefficient of 0.592. It revealed that the genetic relationships among tested accessions were to some extent related with their origin, flower colour, branch type, and genealogy. It further indicated that the RAPD technique is a useful tool for studying the genetic relationships among hybrid Cymbidium cultivars.