Abstract

Nepenthes species are well known for their attractive, ornamental insectcatching pitchers. Characteristics based upon the vegetative parts of these plants are of limited use for taxonomic purposes. This study analyzed genetic relatedness of 13 Nepenthes species dispersed throughout Thailand using the Amplified Fragment Length Polymorphism (AFLP) marker system. The results of DNA exacted from leaves of Nepenthes species using modified Doyle and Doyle (1990) revealed a new method for genomic DNA isolation of both the highest quality and highest quantities of Nepenthes to date. All of the 12 primers screened produced highly reproducible AFLP bands with 100% polymorphism. The number of AFLP fragments generated per primer ranged from 103 to 153 with fragment sizes varying from 100 to 500 bp. A total of 1,461 discernible DNA fragments were detected, of which 73.79% were polymorphic and 26.21% were monomorphic. Nepenthes samples formed a tight cluster in six groups. The dendrogram constructed from AFLP analysis successfully separated the Nepenthes samples individually by geographical area and species. Nepenthes species collected from related ecological habitats appeared in the same groups and differed from the others. The results of this study clearly explain the relationship of Nepenthes species growing in Thailand.