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 necrosis virus translucent veinal necrosis of leaves, necrotic or chlorotic spots of leaves, defoliation, and dieback of shoots that rarely leads to seedling death if infected by the Ghanaian isolate. A following recovery phase of live plants shows limited leaf symptoms. The virus has been transmitted to numerous diagnostically susceptible host species including "Beta vulgaris", "Chenopodium amaranticolor", "Chenopodium quinoa", "Cucumis sativus", "Glycine max", "Gomphrena globosa", "Nicotiana clevelandii", "Nicotiana glutinosa", "Nicotiana tabacum", "Petunia × hybrida", "Phaseolus vulgaris", "Tetragonia tetragonioides", "Theobroma cacao", and "Vigna unguiculata", but these plants are not infected in nature. The strain used to infect these species was the Ghanian isolate.