Résumé
Cacao (Theobroma cacao L.) was cultivated in Central America over two thousand years ago. The type of cacao cultivated in this region is comprised within what is called the morphogeographic group Criollo. Cacao populations from the Amazon basin are included in the second morphogeographic group, which is called Forastero. The most cultivated Forastero type until 1950 was called Amelonade because the melon shape of its pods and its geographical origin was the Lower Amazon. Amalonade type was introduced into Africa from Bahia in Brazil. A third morphogeographic group is called Trinitario. Historically, the Trinitario group originated in Trinidad and resulted from natural hybridization between Criollo from Central America and Amelonado from Venezuela. Criollo trees were progressively replaced in the north of South America and in Central America by more vigorous and productive Trinitario and Amelonade. Most cultivated cacao until 1950 consisted of Criollo, Trinitario and Amelonade. Since 1950, material collected in the thirties and forties from the Upper Amazon region became world wide used in genetic programs. In order to gain a better understanding of the origin and the genetic basis of the cacao varieties cutivated before the utilization of germplasm collected in the Upper Amazon, a study was carried out, using RFLP and microsatellite markers. Samples from Brazil, Venezuela, Colombia, Panama, Trinidad, Costa Rica, Nicaragua, Mexico, Ivory Coast and Cameroon were analyzed. Thanks to molecular markers, it was possible to clearly identify two genotypes at the origin of the traditional varieties (Criollo, Amelonado and Trinitario, independently of its geographical origin). (Texte intégral)