PHENETIC ANALYSES OF TENGKAWANG (SHOREA SPP., DIPTEROCARPACEAE)

Abstract

Tengkawang is referred to a group of approximately 16 species of Shorea producing illipe butter from their kernels.  The name Tengkawang mostly referred to the Bornean Illipe Nut, even though they are not restrictly distributed in Borneo.  Nine of the 16 species belonging to Shorea Section Pachycarpae , two species of Section Brachypterae , three species of Section Mutica and two species of Section Shorea . Recent phylogenetic studies based on molecular markers considered Section Pachycarpae tend to form a monophyletic group.  This present study was aimed to investigate the nature of groupings within Tengkawang and their relatedness based on phenotypic traits.  Thirteen species of Shorea and one species of Hopea as an outgroup were selected to perform a phenetic analysis. An UPGMA dendrogram of Tengkawang was obtained using average taxonomic distance.  Cluster analysis indicated that genetic distance (Dist coefficient) varied from 0.92 to 0.24.  Two main groups were formed, first group contained exclusively Shorea Section Pachycarpae and second group consisted of the remaining species from various Sections  The principal Component Analysis (PCA) was also performed and showed the relative position of 13 of Tengkawang in two-dimension.  The PCA has also identified 27 morphological traits having important roles in the grouping of Shorea section Pachycarpae . A comparative phylogenetic analysis using several chloroplast genes was also in accordance to the results of phenetic analysis, and that the Bornean endemic Shorea section Pachycarpae was a monophyletic group.