Isozyme variation in a number of populations of Theobroma cacao L. obtained through various sampling regimes

Summary Isozyme polymorphism in four enzyme systems was used to estimate the genetic diversity in nine populations of Theobroma cacao L. The distribution of allelic variation observed in this study was inconsistent with the currently held view that the Upper Amazon region of Peru is the centre of cacao genetic diversity. All the populations analysed from this area of Peru were genetically similar, and contained a low level of isozyme polymorphism. It is argued that this is a result of genuine low diversity in the region rather than a sampling artifact. If a centre of diversity of wild cacao truly exists, this work indicates that it lies further north in Ecuador and Colombia.Although they are morphologically highly variable, Trinitario cacao populations derived from cultivation are currently accorded low priority for conservation. This phenotypic variation was observed to be reflected in high levels of isozyme polymorphism. It is suggested that the present strategy for the conservation of cacao germplasm, which accords priority to the Upper Amazon region of Peru while neglecting the Carribbean should be reconsidered.