New research led by the Royal Botanic Garden Edinburgh shows that cacao trees evolved earlier than previously thought – around the time the Andes were being formed in South America. Because of its age, cacao may also have had enough time to diversify genetically, suggesting that new flavours of chocolate may be waiting to be discovered.
Chocolate, produced from seeds of the cacao tree, Theobroma cacao, is one of the most popular flavours in the world, worth around £66 billion a year. However, there are fears the industry will fail to cope with growing worldwide demand.
The main problem is the lack of genetic variation in cultivated cacao, which makes it vulnerable to pests and blights and also puts trees at risk from climate change, both of which issues jeopardise the long-term sustainability of the industry.
Dr James Richardson, a tropical botanist at the Botanics, who led the research, found that Theobroma cacao is one of the oldest species in the genus Theobroma, having evolved around ten million years ago.
“Variation within the species may contribute towards improving the chocolate industry”
Dr James Richardson
At the time, the Andes were not yet fully elevated, which explains why cacao trees today grow on both sides of the mountain range.
The species’ early evolutionary origin suggests that cacao has had enough time to diversify genetically, with each wild population adapting to its local habitat. Wild populations of cacao across the Americas may therefore be treasure troves of genetic variation, which could be bred into cultivated strains to make them more resistant to disease and climate change, and perhaps even create new flavours of chocolate.
Dr Richardson, who is based in Colombia, said: “Studies of the evolutionary history of economically important groups are vital to develop agricultural industries and demonstrate the importance of conserving biodiversity in order to contribute towards sustainable development.
“Here we show for the first time that the source of chocolate, Theobroma cacao, is remarkably old for an Amazonian plant species.
“After ten million years of evolution we should not be surprised to see a large amount of variation within the species, some of which might exhibit novel flavours or forms that are resistant to diseases.
“These varieties may contribute towards improving a developing chocolate industry.”
He added: “Because of the great age of chocolate there should be a lot of genetic diversity, and that will mean very likely there are a larger range of flavours available. There might be different types available on the market as a result of investigating the native populations.”
Dr Richardson and the Botanics worked with researchers from the University of Rosario and the University of the Andes in Bogotá, Colombia; the University of Miami, US; and the US Department of Agriculture.
The study is published in the open-access journal Frontiers in Ecology and Evolution.
