Abstract

The objective of the research is to achieve molecular markers for an economical, ornamental plant group in agriculture worldwide. These plants, Cymbidium aloifolium, Cymbidium atropurpureum, Cymbidium bicolor, Cymbidium chloranthum, Cymbidium dayanum, Cymbidium devonianum, Cymbidium ensifolium, Cymbidium finlaysonianum, Cymbidium haematodes, Cymbidium insigne, Cymbidium lancifolium, Cymbidium lowianum, Cymbidium mastersii, Cymbidium munronianum, Cymbidium rectum, Cymbidium roseum, Cymbidium sinense, Cymbidium tigrinum, and Cymbidium tracyanum in Thailand have been explored, collected and identified. DNA barcoding for a species specific marker was performed in order to provide further rapid, accurate, and automatable species identification for plants lacking flowers or having incomplete morphological characteristics and for the young plants that are massively grown on orchid cutting flower farms. The sequences of four standard regions as barcodes were tested for genetic distances. The genetic distances, means nucleotide variations in tag sequences based on rpoB, rpoC1, matK, and trnH-psbA spacer region sequences of the 19 species ranging from 0.012 to 0.546, 0.018 to 0.546, 0.052 to 0.385, and 0.026 to 0.528, respectively. DNA barcoding shows promise for molecular-based identification of Cymbidium species. The sequences have been deposited in GenBank.

Key words: Cymbidium, matK, rpoB, rpoC1, species diversity, trnH-psbA.