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
Cacao yellow mosaic virus it can experimentally infect a number of other dicots including "Chenopodium amaranticolor", "Chenopodium quinoa", "Tetragonia expansa", "Vinca rosea", "Nicotinia clevelandii", and "Nicandra phsalodes". Cacao yellow mosaic virus Cacao yellow mosaic virus (CYMV) is a virus in the family Tymoviridae that infects cacao trees in Sierra Leone. CYMV, like other "Tymoviridae" are non-enveloped viruses, surrounded by a capsid approximately 30 nanometers wide. The viral capsid has T = 3 symmetry. "Tymoviridae" have positive-sense single-stranded RNA genomes approximately 6 kilobases long. In the cacao tree, CYMV infection leads to the appearance of large circular yellow blotches on the leaves. Infected trees are