2015 Volume 84 Issue 3 Pages 243-252
In Thailand, Dendrobium is the most popular crop grown for cut flowers and as a pot plant for local use and export. Some native species are used for hybrid production while some are specific to particular parts of the country and need to be conserved. The sequences of rDNA ITS (ITS1-5.8S-ITS2) and the matK gene were used to reconstruct the phylogenetic relationships of 27 native Dendrobium spp. in Thailand, which are composed of 9 sections: Breviflores, Callista, Dendrobium, Distichophyllum, Formosae, Pedilonum, Rhopalanthe, Stachyobium, and Strongyle. The average levels of nucleotide divergence (p-distances) of matK and rDNA ITS sequences were 1.3% and 11.2%, respectively. The topologies of the phylogenetic trees reconstructed based on matK and rDNA ITS sequences were slightly different. Use of the rDNA ITS sequence was shown to be a more authoritative systematic approach than use of the matK gene sequence in the genus Dendrobium. The result of the combined data (matK-rDNA ITS) was highly similar to the result from rDNA ITS. From rDNA ITS and combined data, the twenty-seven Dendrobium spp. were clearly grouped into two clades with some differences from the morphological classification. The present study provides the first molecular phylogeny of 27 native Dendrobium species in Thailand.
