Genetic diversity and phylogenetic relationships among and within species of oriental cymbidiums based on RAPD analysis

The classifications of oriental cymbidiums that are native to Korea, China, Taiwan and Japan were examined by molecular analysis. A total of 21 cymbidiums, 15 species including three Cymbidium gyokuchin, 4 Cymbidium kanran and 2 Cymbidium goeringii cultivars, were analyzed by using randomly amplified polymorphic DNA (RAPD) to determine the interspecific and intraspecific relationships. Twenty-two primers were used in the RAPD analysis to distinguish, by comparing differences in DNA banding patterns, all species and cultivars. Similarity values ranged from 0.501 for Cymbidium aloifoilum and C. kanran to 0.935 for Cymbidium ensifolium and Cymbidium marginatum with analysis of total bands score. Phylogenetic tree analysis of the RAPD results from the 21 cymbidiums identified specific groupings. The cymbidiums could be divided into two clusters based upon ecological traits. One trait was temperate zone preference, with each cymbidium preferring either an Asian or subtropical temperate zone. The group that comprised the subtropical cymbidiums was C. aloifoilum, Cymbidium insigne and Cymbidium lowianum. Additionally, we found that Cymbidium lancifolium and Cymbidium aspidistrifolium could be separated based on different flowering physiology and unique leaf form. The groups identified by morphological, physiological and ecological characteristics were in full agreement with those determined by RAPD analysis. The phylogenetic tree derived from the RAPD results was similar to that of the traditional classification. The data acquired from this study could be used for identification and classification of other orchid genera and oriental cymbidium.