The scientists sequenced the DNA of Theobroma cacao. The Maya reportedly domesticated this variety of Theobroma cacao, Criollo, around 3,000 years ago in Central America. It’s a rare tree; currently, many growers opt for hybrid cacao trees that offer lower quality chocolate but are more resistant to disease.
The Penn State researchers write in Nature Genetics, according to a university press release, “consumers have shown an increased interest for high-quality chocolate made with cocoa of good quality and for dark chocolate, containing a higher percentage of cocoa, while also taking into account environmental and ethical criteria for cocoa production.”
The team identified various gene families that may play a role in improving cacao trees and fruit. They can do so by either by enhancing their characteristics or providing protection from fungal diseases and insects that affect cacao trees.
“Our analysis of the Criollo genome has uncovered the genetic basis of pathways leading to the most important quality traits of chocolate — oil, flavonoid and terpene biosynthesis,” said Siela Maximova, associate professor of horticulture, Penn State, and a member of the research team, in the press release. “It has also led to the discovery of hundreds of genes potentially involved in pathogen resistance, all of which can be used to accelerate the development of elite varieties of cacao in the future.”
The press release goes on to say researchers are “interested in specific gene families that could link to specific cocoa qualities or disease resistance.” They hope their work in mapping these genes will lead to a source of genes involved in variations in the plant that play a role in accelerating plant breeding programs.
