Molecular Phylogeny of Dtpterocarp Specles Ustng Nucleotlde sequences of Trro Non-codrng Regtons rn Chloroplast DNA

A total of 53 dipterocarp species belonging to ten genera were studied to examine phylogenetic relationships using the sequences of iwo non-coding regions in chloroplast DNA. Phylogenetic analysis showed the Selangan Batu, Yellow Meranti and While Meranti of the genus Shorea were monophyletic, while the Red Meranti was divided into three nalural clades. The relationships in the Red Meranti could not be ascertained because of an insufficient number ofnucleotide substitutions. The White Meranti was cluslered with sect. Pentacme and siluated in an outer position of the gems Hopea, Neobalanocarpus and Parashorec although the bootstrap probability was not high. Two of the three deciduous Shorea species collected in Thailand, one belonging lo White Meruti and the other to sect. Pentacme based on morphological and anatomical evidence, were found to constitute a monophyletic group clustering with the other White Meranties. The third species in the Selangan Batu was clustered with the other Selangan Batus. This suggests that the deciduous character in the genus Shoreahas evolved independently in differentlineages. sect. Richetioides. The genera Shorea and Hopea werc more divergenl than the other genera. These resulls suggest that they are the groups of phylogenetically more diversified species. Our results indicated that the White Meranti is monophyletic with sect. Pentacme(bootstrap probability was 97.2Vo) and it was the first group that diverged from the other Slprea species. Both the White Meranti and sect. Pentacme have unequal cotyledons and contain silica in the cells of radial tissue, while in the other groups of Shorea cotyledons are equal and silica is mostly absent (Ashton, L982). These observations are consistent with the classification mentioned above. The Selangan Batu group usually produces more hard timber compared with other groups (Symington, L943). In our phylogenetic tree, the species belonging to the Selangan Batu group was monophyletic (bootsfrap probability was 79.3Vo). The Yellow Meranti group is distinguished from the other groups by the character of the anther, wood and bark anatomy and the yellow-brown heartwood (Symington, 1943; Ashton, L982; Newman et al., 1996). Our phylogenetic tree showed that the Yellow Meranti group is also a monophyletic group (bootstrap probability was 96.9Vo). In this study, the molecular tree was consistent with the morphological classification except for the Red Meranti group. The Red Meranties have pale to dark red or occasionally brown color of heartwood (Meijea 1964). The Red Meranti group comprised three natural clades. Shorea ferruginea, S. macroptera ssp. macropterifulia and S. acuta were clustered (bootstrap probability was 83.6Vo), and this conforms with Ashton's (1982) sect. Mutica subsect. lzriculnta.Howeve! most of the other relationships in the Red Meranti group could not be ascertained because the bootstrap probabilities were very low The data in this study are insufficient for the classification of species in the Red Meranti group. Our tree, therefore, indicated that the