Genetic diversity and structure of Hopea bilitonensis, an endemic Dipterocarp from Belitung Island, Indonesia

Hopea bilitonensis Ashton (Dipterocarpaceae) is a small tree endemic to some islands on the east coast of Sumatra, particularly Belitung Island, Indonesia, and the northwest of Malaysia. Forest fragmentation and degradation in Belitung Island could affect population and genetic diversity of this species. The main objectives of this study are to examine genetic diversity and structure of H. bilitonensis on Belitung Island, Sumatra. Multiplexed ISSR genotyping by sequencing (MIG-seq) is used for genotyping and SNP detection. Genetic diversity and structure were determined using STRUCTURE analysis. We found that genetic diversity of H. bilitonensis is lower in seedlings than in juvenile and mature individuals. In contrast, inbreeding coefficient is lower in mature individuals than in the seedlings and juveniles. Genetic clusters (K=3) are detected in the early regeneration stages. These genetic structure separates the population of seedling and juvenile stages more clearly than in the mature individuals. Representation of these genetic clusters is essential when collecting propagation material for ex-situ conservation and establishing new populations of this threatened species to ensure its sustainability.