Tuesday, December 13, 2016

The genome sequence of the most widely cultivated cacao type

The cacao tree (Theobroma cacao L.) is a neotropical species native to Amazonian lowland rainforests and is now grown in more than 50 countries throughout the humid tropics. T. cacao is a member of the Malvaceae family, and its beans (seeds), harvested from pods (fruits), are used for the chocolate, confectionery, and cosmetic industries. Cacao production is essential to the livelihoods of 40 to 50 million people worldwide, including the smallholder farmers who cultivate the crop, who number more than 5 million. Cacao-growing regions are also largely centered in important biodiversity hotspots and in proximity to 13 of the world's most biologically diverse regions.

Recent molecular analyses have permitted cacao germplasm classification into 10 major clusters or groups: Amelonado, Contamana, Criollo, Curaray, Guiana, Iquitos, Maraňón, Nanay, Nacional, and Purús. Compared with traditional cacao classification schemes, this new system more accurately reflects the genetic diversity available to breeders.

Because of its high yield and disease resistance, the most ubiquitous clone in large cacao plantations in Latin America is CCN 51. It is also the optimal parent in many breeding programs, owing to its favorable combining ability for yield. Unfortunately, it has a rather undesirable flavor profile because of its high acidity and astringency, and also because it lacks desirable floral aromas.

CCN 51 tree

On the other hand, the genome sequence of a Criollo genotype was recently reported. Although this cacao type is genetically distinct, it is a poor representative of the cacao types cultivated worldwide. In an effort to enhance the accuracy and speed of traditional cacao breeding, is sequenced the genome of Matina, a self-compatible and highly homozygous genotype that is more representative of the cacao cultivated worldwide. In conclusion, the theobroma cacao is divided in many group which they will have many characteristics, from the color, flavor, and size of the fruit; all this will depend on the type of plant, genotype that has or type of soil on which it was cultivated. However, cacao will be one of the organic products most bought in the world, for its different uses.

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