GENETIC DIFFERENTIATION OF COCOA (THEOBROMA-CACAO L) POPULATIONS REVEALED BY RAPD ANALYSIS

In order to preserve and exploit the valuable genetic resources of tro pical forest trees, such as cocoa, a systematic assessment of the avai lable genetic variability is necessary. The approach we have used is b ased on a simple mini-prep DNA extraction procedure together with a po lymerase-chain-reaction-(PCR)-based polymorphic assay procedure (RAPD) . Twenty-five cocoa accessions: IMCs and PAs collected from Peru and L CTEENs collected from Ecuador, which are difficult to distinguish usin g morphological or biochemical descriptors, were uniquely fingerprinte d using a minimum of three oligonucleotide primers. Analysis of the va riability detected using RAPDs clearly discriminated between the geogr aphical origin of the three cocoa populations. Partitioning of variabi lity into within and between population components revealed that most variation was detected within a population. The potential of RAPD anal ysis to facilitate the rationalization of field gene banks and provide accurate estimates of diversity to allow optimization of collecting s trategies is discussed.