Assessment of phylogenetic relationship among twenty Curcuma species in Thailand using amplified fragment length polymorphism marker

Plants in the genus Curcuma are a rhizomatous perennial herb which is widely distributed in Thailand. It has long been known for their uses as folk medicines, foods, spices, and cosmetics. However, the identification of plants in the genus Curcuma is very difficult due to morphological similarity in the early flowering stage. Recently, the molecular technique is one of the reliable and powerful tools for plant identification. In this study, the genetic relationship among twenty Curcuma species from Thailand was accessed by the amplified fragment length polymorphism (AFLP) method. AFLP fingerprint showed 98.54% highly polymorphisms with the number of bands (617 bands) ranging between 48 and 80 bands. The dendrogram generated from the unweighted pair group method of the arithmetic average could separate these Curcuma species into three major clusters. Cluster I can be subdivided into IA, which composed of Curcuma parviflora, Curcuma sparganiifolia, Curcuma alismatifolia, Curcuma larsenii, Curcuma Gracillima, and Curcuma rhabdota with similarity index (SI) 0.7926–0.9358 and IB composed of Curcuma petiolata and Curcuma rubrobracteata with the SI 0.9240. Cluster II can be subdivided into IIA being composed of Curcuma longa, Curcuma Zedoaria, and Curcuma aromatica with the SI 0.8989–0.9071, whereas Cluster IIB was composed of Curcuma leucorrhiza, Curcuma aeruginosa, Curcuma comosa, Curcuma mangga, Curcuma angustifolia, Curcuma amada, Curcuma sessilis, and Curcuma albicoma with the SI 0.8236–0.9500. Cluster III belongs to Curcuma singularis and Alpinia galanga (outgroup plant), which clearly separated into different clusters from twenty Curcuma species. In summary, the ten successful AFLP primer combinations could be used to determine the genetic relationship among closely related twenty Curcuma species in Thailand.