Durio testudinarius is an indigenous durian species classified under the Malvaceae family, primarily distributed within the Borneo region. It has a specific feature of bearing fruit from the main trunk. Understanding its genetic diversity is crucial for its utilization. This study aimed to analyze the genetic diversity and phylogenetic relationships of five D. testudinarius accessions from West Kalimantan. A sample of D. testudinarius from five West Kalimantan populations, six Durio species (D. graveolens, D. acutifolius, D. lanceolatus, D. dulcis, D. kutejensis, and D. oxleyanus) and 17 Durio species NCBI dataset underwent genetic diversity and phylogenetic analysis using DNA barcoding markers from three chloroplast regions (matK, rbcL, and trnL-trnF intergenic spacer) and a nuclear DNA Internal Transcribed Spacer (ITS) region. The ClustalW alignment of the five D. testudinarius accessions revealed limited nucleotide variation in the chloroplast regions but significant variation in the ITS region, relating to genetic variation in the nuclear genome. Phylogenetic analysis showed that D. testudinarius is genetically more similar to D. beccarianus, which confirms that they flower on the trunk. This DNA barcoding data improves genetic libraries and assists conservation and breeding programs by revealing D. testudinarius and related species’ genetic variation.

Keywords: Chloroplast marker, ITS spacer, nucleotide variation, species phylogenetic

Key findings: This research offers valuable insights into genetic variation by providing DNA barcoding sequence data on four barcodes for D. testudinarius from West Kalimantan. This contribution enriches existing DNA libraries, supporting conservation efforts and plant breeding programs.