A new study has traced the deep evolutionary history of Theobroma cacao, the plant behind chocolate, and its wild relatives, offering fresh clues for future climate-resilient crops. Using five WRKY gene fragments from 42 samples across Theobroma, Guazuma and Glossostemon, researcher reconstructed their family tree with BEAST and mapped ancestral ranges with RASP.
The results suggest that Theobromateae began diverging about 37.3 million years ago. Theobroma formed a single evolutionary group, while T. cacao separated from its closest relative around 17.59 million years ago and diversified into modern genetic variants about 1.72 million years ago.
The study points to Amazonia as the probable birthplace of Theobroma, before the genus spread northward into Choco, Central America, the Guyana Shield and Guyana. By contrast, Guazuma and Glossostemon appear better adapted to drier environments. Glossostemon, now restricted to Arabia, may represent an older, desert-adapted lineage.
We argue that these wild relatives could help scientists understand drought tolerance in cacao. As climate change threatens tropical agriculture, the genetic legacy of chocolate’s relatives may become increasingly valuable. The research also underlines Amazonia’s importance as a cradle of biodiversity and calls for broader genome-wide sampling to test these evolutionary patterns further in detail.
