A recent study on the origin of the cacao cultivated by the Mayas.
Criollo cacao (Theobroma cacao ssp. cacao) was cultivated by the Mayas over 2500 years ago.
It has been suggested that Criollo cacao originated in Central America and that it evolved independently from the cacao populations in the Amazon basin.
Cacao populations from the Amazon basin are included in the second morpho-geographic group : Forastero and are assigned to Theobroma cacao ssp sphaerocarpum.
To gain insight into the origin and genetic basis of the Criollo from Central America analysis were performed on a sample that avoided mixing pure Criollo with Criollo which might have been introgressed with Forastero genes.
These two types were distinguished as Ancient and Modern Criollo.
In contrast to previous studies, Ancient Criollo formerly classified as "wild", was found to form a closely related group together with Ancient Criollo from South America.
The ancient Criollo trees were also closer to Columbian, Ecuadorian Forastero types than these Colombian - Ecuadorian trees were to other South American Forastero types.
There was low genetic diversity within the Ancient Criollo Group.
The results suggest that the Ancient Criollo types represent the original Criollo group.
The results also imply that this group does not represent a separate subspecies and that it probably originated from a few types in South America that may have spread by men (or animal) within Central America.
Cacao from the Lacandona rainforest was found to be identical at a molecular level to types cultivated by the Mayas (those found in the sinkholes or "cenotes" of Yucatan, the Pacific Coast of Mexico and Belize) and to individuals from the regions of south-western Venezuela and north-eastern Colombia.
Therefore the population consisting of trees found at the Lacandona rainforest should neither be considered wild nor as originating from this region.
Another element that must be considered is the absence of evidence of the presence of Theobroma in the forests of Chiapas before the human colonization.
In addition, in the Lacandona rainforest, vestiges of the Mayan civilisation were frequently found. Thus, the presence of Criollo cacao trees in the Lacandona rainforest may be a remnant of cacao cultivation by the Mayas.
As Ancient Criollo individuals are more related to Forastero from Colombia and Ecuador, than the latter are to other Forastero individuals from French Guiana, the Orinoco, the Lower Amazon or some from Peru, the Criollo group does not form a separate subspecies (ssp cacao) from the one comprising individuals from South America (ssp sphaerocorpum).
In fact, all indicates a recent origin for the name Forastero.
Classification of species.
Since genetic distances between some Forastero individuals are equivalent to those observed between some Forastero and Ancient Criollo, a classification of cacao based on Criollo and Forastero has no genetic base.
Indeed, this classification first proposed by Morris (1882) was simply based on the terms used by the Venezuelan cacao producers.
At that time the term Criollo was employed to distinguish the local cultivated tree, with a specific pod type from the introduced foreign type.