GENETIC VARIATION OF SAGO PALM (Metroxylon sagu Rottb.) SAMPLES FROM MINDANAO, PHILIPPINES USING INTERNAL TRANSCRIBED SPACER ANALYSIS.

The sago palm is an emerging important food and energy source in the Philippines. There is limited information on the nature of its distribution in the Philippines. This study presents a phylogenetic tree hinting of the possible influence of geographical distribution to Internal Transcribed Spacer (ITS) polymorphism in sago palm. Internal Transcribed Spacer (ITS) Analysis was employed to assess intra-individual heterogeneity and genetic divergence within the sago morphotypes. The variables under observation were armature type (spiny or non-spiny), maturity, and environment, and combination of these variables yielded eight morphotype samples. Deduced gene sequences of the samples showed a relatively low mean GC% of 50.5%, compared to expected 65.8% from the Metroxylon salomonense (Warb.) Becc. outgroup. This phenomenon was attributed to possible cytosine methylation that led to mutability of GC base pair. Furthermore, branching pattern of ITS sequence divergence for both Neighbour-Joining and Maximum Likelihood methods was observed to be influenced by geographic distribution as non-spiny samples collected from Prosperidad clustered into a monophyletic group with the M. salomonense (Warb.) Becc. Outgroup from Papua New Guinea while the spiny samples from Tagum City diverged into a different group. The sago palm spine is a morphological trait that could be used for the differentiation of sago morphotypes within a small population of limited diversity. This trait is of particular interest in breeding due to its possible influence on important agronomic traits such as yield and resistance to pests and diseases. [ABSTRACT FROM AUTHOR]