Alpinia zerumbet and its related taxa (Zingiberaceae), such as Alpinia formosana, Alpinia intermedia, Alpinia uraiensis, and Alpinia sp., are native to the subtropical and tropical regions in East Asia, including the Nansei Islands. Owing to their morphological similarities, it is difficult to distinguish A. zerumbet from the related taxa. Therefore, a reliable DNA characterization method is required for the breeding and utilization of A. zerumbet and related taxa. Herein, several analytical methodologies have been proposed for the identification of Alpinia species. We showed that a set of random amplified polymorphic DNA (RAPD) markers, high-resolution melting (HRM) analysis, and genotyping by random amplicon sequencing-direct (GRAS-Di) are important tools for understanding the genetic diversity and variation of the Alpinia species growing in the Nansei Islands. The RAPD markers effectively distinguished A. zerumbet from the related taxa. Furthermore, the HRM analysis of nuclear ribosomal DNA internal transcribed spacer 1 revealed clear differences between the species. The phylogenetic analysis using GRAS-Di revealed that each Alpinia species formed independent species-specific subclusters on the phylogenetic tree. Using the molecular markers presented in this study, A. zerumbet and related taxa can be easily and accurately distinguished from each other without morphological characterisation.
Narusaka et al. (Tue,) studied this question.