Genetic structure and diversity of coconut (Cocos nucifera Linn.) in Southern Tagalog, Philippines as revealed by Inverse Sequence-Tagged Repeat (ISTR) analysis

Issue Date

9-2007

Abstract

This study was conducted to determine the diversity and explore the presence of discrete populations of indigenous tall coconut palms in eight locations in Santo Tomas and Tanauan, Batangas; Lukban, Mauban and Pitogo, Quezon; and Liliw, Laguna, in the Southern Tagalog region of the Philippines. Inverse sequence-tagged repeat (ISTR) analysis using four primer combinations generated 65 dominant-type markers. Shannon-Weaver diversity index, percent polymorphism and heterozygosity and genetic differentiation between population pairs were determined. High genetic diversity values were obtained within collection sites. Polymorphism within site averaged 86.15% over all populations and loci. Heterozygozity within site averaged 0.30 calculated over all loci and palms studied. Wright's fixation index (Fst) of 0.24 among populations calculated for all loci considered simultaneously was significant. Almost all pairwise values of Fst and probability of population differentiation were significant from F-statistics and Fisher's combined probability tests, respectively, indicating that populations from Banjo West, Gangahin, Novaliches and San Miguel are discrete. The Fst and differences in estimated allele frequencies were insignificant between Tinurik and Laguna Tall as well as between Santiago and Piis, resulting from movement of seednuts between localities. Shannon-Weaver diversity index among sites was low at 2.95%. A high proportion of the total diversity (97.05%) remains within populations. No geographical trends were observed among the populations based on Nei's genetic distances.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Volume

90

Issue

3

Page

196-205

Document Type

Article

Language

English

Subject

Gene flow, Genetic distances, Inverse sequence-tagged repeat analysis, Population differentiation, Shannon-Weaver diversity index

Digital Copy

none

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