Cacao domestication II: progenitor germplasm of the Trinitario cacao cultivar.

Cacao (Theobroma cacao L.) has been cultivated in Central America since pre-Columbian times. The type of cacao cultivated in this region was called Criollo; cacao populations from the Amazon basin were called Forastero. The type of Forastero most commonly cultivated until 1950 was named Amelonado. Historical data show Trinitario cacao to have originated in Trinidad, resulting from natural hybridisation between Criollo and Amelonado Forastero. Doubts persist on the source of the Amelonado Forastero involved in the origin of Trinitario; the Amelonado parent may have come from the Lower Amazon, the Orinoco or the Guyanas. Most of the cacao cultivated worldwide until 1950 consisted of Criollo, Trinitario and Amelonado. From the early 1950s, Forastero material collected in the Upper Amazon region during the 1930s and 1940s began to be employed in breeding programmes. To gain a better understanding of the origin and the genetic basis of the cacao cultivars exploited before the utilisation of germplasm collected in the Upper Amazon, a study was carried out using restriction fragment length polymorphism and microsatellite markers. Trinitario samples from 17 countries were analysed. With molecular markers, it was possible to clearly identify three main genotypes (represented by clones SP1, MAT1-6 and SIAL70) implicated in the origin of most Trinitario clones.