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 swollen-shoot virus ambitious and costly eradication effort of any country in the world against a viral plant disease. Cacao swollen-shoot virus (CSSV) principally infects "Theobroma cacao" (cacao tree) and has a major effect on crop yields. Within one year of infection yields decrease by 25%, and within two years by 50%. The trees are usually killed within 3 to 4 years. Symptoms vary depending on the strain of virus. Main symptoms include: leaf chlorosis (interveinal), root necrosis, red vein banding in young leaves, small mottled pods, and stem/root swelling followed by die-back. CSSV has also been isolated from alternative hosts "Cola chlamydanta",