Assessing Genetic Diversity of Asian-based Rubber Populations using SSR and Multivariate Statistics in the Philippines

Abstract

Assessing genetic diversity of rubber populations is important for the effective utilization of rubber genetic resources. Diversity indices such as number of alleles (Na), observed heterozygosity (Ho), gene diversity (GD), polymorphism information content (PIC) and power of discrimination (PD) along with multivariate statistics such as principal component analysis (PCA) and clustering analysis were used in the study. Twenty-two SSR markers had means 5.09 Na, 0.579 Ho, 0.677 GD, 0.643 PIC and 0.785 PD for 63 rubber clones comprised of 34 Indonesian and 29 Malaysian clones. Malaysian subpopulation had 3.59 Na per clone greater than Indonesian subpopulation of 2.97 Na per clone. PCA detected 66.08% total variation for eight principal components (PCs). PC1, PC2 and PC3 contributed 13.24% variation (v) with 2.91 eigenvalue (e), 10.2% v with 2.24 e and 8.86% v with 1.95 e, respectively. Clustering analysis revealed 0.237 genetic similarity and ten clusters for all clones. Clusters will be the basis for making more genetically diverse hybrids while PC1 member clones will be the basis for considering genetically broad base parent. The high genetic diversity found in the Asian-based rubber populations and complementing results of multivariate statistics can optimize the selection and breeding of rubber genetic resources in the Philippines.

Keywords: Asian-based Rubber Populations, Genetic Diversity, Multivariate Statistics, SSR Diversity