Assessment of Durian Diversity and Its Wild Relatives (Durio spp.) Based on Leaf Morphology and Molecular Marker

Durian (Durio spp.) is native to Southeast Asia and has potential for development. However, some species are threatened due to deforestation and extensive land conversion. This study aimed to determine the genetic diversity and relationships of durian and wild relatives (Durio spp.) on the Indonesia Island Borneo using a leaf morphology and DNA barcoding (matK) marker. In this study, 15 durian samples from this region were used, excluding ‘Monthong’ (Durio zibethinus) and ‘Bengang’ (Neesia strigosa) as the outgroups from the GenBank database. The leaf morphology was analyzed descriptively, whereas the genetic diversity was by the nucleotide diversity index (π%). The relationship of durians was revealed by the maximum likelihood (ML) method and examined with the bootstrap statistics for 1000 replicates, also confirmed by the PCA (principal component analysis). Based on the leaf morphology, the durians are divided into five forms, i.e., obovate-lanceolate, elliptic, ovate, oblong, and linear-oblong. ‘Pampaken’ and ‘Pampaken Burung Kecil’ indicated the earliest form (obovate-lanceolate), whereas the linear-oblong was by ‘Kamundai.’ Following the molecular marker, it was seen that the durians have low genetic diversity (π%) with only 0.015. However, phylogenetically, the durians were separated into four similar clades or groups for ML and PCA. In this instance, it has appeared that most of the durians evaluated in the current study have close relationships, except for the taxa with the farthest relationship. The results provide valuable information for the local and global durian conservation mission, including future breeding programs.