Genetic diversity of cultivated mangosteen and its wild relatives (Garcinia spp.) based on leaf morphology and molecular markers

Abstract

The mangosteen (Garcinia mangostana L.) germplasm still has limitations in fruit quality, drought tolerance, and susceptibility to pests or diseases. This study investigated the genetic diversity and relationships of mangosteen with its wild relatives (Garcinia spp.) based on leaf morphology and the internal transcribed spacer (ITS) region, including its secondary structure. Based on leaf morphology, the mangosteen and its wild relatives generally showed a low genetic diversity. However, the leaf texture and pubescence had a high genetic diversity (0.71 and 0.77, respectively). Furthermore, based on the ITS markers, the genetic diversity of Garcinia at the interspecies level was much higher than that at the intraspecies one (0.043 and 0.005, respectively). The unweighted pair group method with the arithmetic average (UPGMA) revealed that mangosteen is grouped into four main clusters, with ‘Manggis Banjar’ and ‘Palembang’ in the same cluster. Similarly, the ITS positioned Garcinia into several clades, with ‘Manggis Banjar’, ‘Kandangan’ and ‘Palembang’ grouped into a similar clade. The biochemical reconstruction showed that Garcinia has unique ITS secondary structures, i.e., ring and four-helix models. Even though the cultivated mangosteen and its wild relatives had low diversity based on leaf morphology, the ITS markers showed a high genetic diversity. Furthermore, the reconstruction of the ITS secondary structure has supported this germplasm’s phylogenetic tree.