Global Phylogenetic Insights into the Moth Orchid (Phalaenopsis amabilis) Population from the Meratus Mountains of South Kalimantan, Indonesia

Phalaenopsis amabilis constitutes one of the most valuable and economically significant orchids (ornamental plants) worldwide. The present study aimed to investigate the genetic diversity and phylogenetic relationships of the moth orchid (Phalaenopsis amabilis) population native to the Meratus Mountains of South Kalimantan, Indonesia, using the matK marker. Sixty-one samples of Phalaenopsis, comprising six of Phalaenopsis amabilis from the Meratus Mountains of South Kalimantan, Indonesia, and 55 of another Phalaenopsis species from GenBank, were molecularly characterized using the matK marker to assess genetic diversity and phylogenetic relationships. Genetic diversity was determined using the Maximum Composite Likelihood method, and phylogenetic relationships were estimated using the Kimura 2-Parameter Maximum Likelihood method. In this study, moth orchid populations had lower levels of matK polymorphism at the intraspecific than at the interspecific level, with values of 10.07% and 47.91%, respectively. Similarly, this is directly proportional to the genetic diversity at both levels, which is lower (0.016) at the intraspecific level than at the interspecific level (0.062). However, this marker reveals unique phylogenetic relationships in Phalaenopsis, both locally and globally, with P. amabilis ‘Halong 2’ closely related to three similar species from Singapore, Japan, and the USA. At the same time, all samples of P. amabilis are closely related to two other Phalaenopsis species, i.e., P. sanderiana and P. aphrodite. The findings are expected to provide critical insights to guide future conservation strategies and targeted breeding programs for these native orchids.