Molecular Evaluation of the Philippine Best Rubber Clones using Genomic-based Simple Sequence Repeats

Abstract

To date there are only nine best rubber clones in the Philippines with little knowledge about its molecular information. Nineteen genomic-based simple sequence repeats' (G-SSRs) good genome coverage had provided enough data in evaluating the Philippine best rubber clones (five PB, three RRIM and one Philippine or Phil derived clones) along with two Phil check clones. G-SSRs derived 72 alleles in all with means N, N_e, H_o, and PIC of 3.789, 2.284, 0.569 and 0.508 per G-SSR, respectively. Nine G-SSRs however detected 16 private alleles. AMOVA also revealed 6.37%, 19.26% and 74.37% molecular variance between groups, between and within clones, respectively, with corresponding F_ST of 0.064. While genetic proximity had a range of 0.184 to 0.487 with corresponding neighborhood-joining tree suggested no similar clones, three groups (PB, RRIM and Phil groups) had delta K of two based from Bayesian structure analysis. Group 1 had RRIM600, RRIM712 and RRIM901 while group 2 had PB217, PB235, PB260, PB311, PB330, SMRX1, UPLBPlant1 and USM1. G-SSRs are suitable for extracting molecular information and distinct alleles, which can be used as reference to authenticate the best rubber clones in the Philippines. Bayesian structure analysis on the other hand assured better resampling strategy and found admixtures. Furthermore, rubber is highly structured in individual level that indicates these clones should be utilized to broaden genetic variability of the Philippine rubber.