Indonesia is the leading global producer of Uncaria gambir (W. Hunter) Roxb., with West Sumatra having the largest plantation. The assessment of haplotype diversity is crucial for the production and quality of gambir in West Sumatra, Indonesia. The following study utilized ITS markers to ascertain the haplotype diversity in 28 accessions of U. gambir and one wild gambir species (U. homomalla) from four populations in main plantation areas located in West Sumatra, Indonesia. The research isolated, amplified, and sequenced the DNA. The assessment of genetic differentiation utilized various bioinformatics tools, including BioEdit for sequence alignment, DnaSP for detecting polymorphisms and analyzing haplotype diversity, and MEGA 11. The analysis of 28 accessions of U. gambir and one wild gambir species (U. homomalla) among four examined populations, identified seven distinct haplotypes (H1–H7). Haplotype diversity emerged to be moderate among all the groups (Hd = 0.633). The population of Taratak Tempatih demonstrated the greatest haplotype variety (Hd = 0.90), while the population of Simpang Kapuak exhibited the lowest diversity (Hd = 0), while all populations possessed the identical haplotype (H1). The genetic identity of Udang, Riau Besar, Riau Kecil, and Cubadak accessions will support seedling selection and breeding programs.

Keywords: Uncaria gambir (W. Hunter) Roxb., landraces, genetic uniformity, haplotype diversity, ITS, phylogenetic relationship

Key findings: The presented study identified seven distinct haplotypes in U. gambir (W. Hunter) Roxb., demonstrating the highest genetic diversity, using ITS markers. The highest haplotype diversity indicates low genetic uniformity, affecting gambir production and quality. This genetic diversity is crucial for the conservation of gambir landraces in West Sumatra, Indonesia.