Chocolate lowland climate in the narrow band of latitudes where cacao is grown (20 degrees north and south of the equator), the commercial company Mars, Incorporated and the University of California, Berkeley are conducting genomic research in 2017–18 to improve the survivability of cacao plants in hot climates. Chocolate is made from cocoa beans, the dried and fermented seeds of the cacao tree ("Theobroma cacao"), a small, 4–8 m tall (15–26 ft tall) evergreen tree native to the deep tropical region of the Americas. Recent genetic studies suggest the most common genotype of the plant originated in the Amazon basin and
Theobroma cacao until practices changed in the 21st century, the fermented pulp may be distilled into an alcoholic beverage. Each seed contains a significant amount of fat (40–50%) as cocoa butter. The fruit's active constituent is the stimulant theobromine, a compound similar to caffeine. Cacao ("Theobroma cacao") belongs to the genus "Theobroma" classified under the subfamily Byttnerioideae of the mallow family Malvaceae. Cacao is one of 17 species of "Theobroma". In 2008, researchers proposed a new classification based upon morphological, geographic, and genomic criteria: 10 groups have been named according to their geographic origin or the traditional cultivar name. These groups are: