Nucleotide Diversity of a Nuclear and Four Chloroplast DNA Regions in Rare Tropical Wood Species of Dalbergia in Vietnam: A DNA Barcode Identifying Utility

Five nucleotide regions (a nuclear ribosomal DNA internal transcribed sequence (ITS) and four chloroplast DNA fragments (trnL intron, matK-designed, matK-barcode and psbA-trnH spacer) were used for the assesment nucleotide diversity for the eight woody tree species in genus Dalbergia (Dalbergia oliveri Gamble ex Prain, Dalbergia cochinchinensis Pierre, Dalbergia nigrescens Kurz, Dalbergia tonkinensis Prain, Dalbergia assamica Bentham, Dalbergia entadoides Pierre ex Prain, Dalbergia hancei Bentham and Dalbergia dialoides Pierre Niyomdham) of Vietnam. The number of variable sites for individual loci ranged from 13 (psbA-trnH spacer) to 111 (ITS). The highest divergence region was ITS (7.4  %), followed by psbA-trnH spacer (2.2 %), trnL intron (1.5 %), matK-designed (1.2 %) and matK-barcode (1.3 %). Analyses based on threshold genetic distances, Phylogenetic trees-based and nucleotide character differences methods showed that only nuclear ITS region is the best nucleotide diversity of rare woody tree species in Dalbergia genus. Therefore, it can be used as an identification of eight Dalbergia species.