Exploring the natural genetic diversity of cocoa’s wild relatives for crop improvement

Written by: Ana M. Bossa-Castro, James E. Richardson, Laura Tatiana Morales Mancera, Martha Lucía Cepeda-Hernández, Jorge Duitama, Wilfried Haerty, Federica Di Palma and Martha Vives. Researchers from the Natural Diversity Programme.

Worldwide, only a small portion of the genetic diversity of cocoa (Theobroma cacao) is currently used to produce chocolate. Meanwhile, cocoa farmers and producers in Colombia face serious challenges from threats such as pathogens and climate change, and from the international limits on the permitted cadmium level in cocoa beans.

The natural diversity of wild cocoa varieties has enormous potential to address the challenges of cocoa production. For this reason, cocoa is one of the subjects of GROW Colombia’s Natural Diversity programme. Our research will help us discover how these varieties have evolved over time.

To understand the genetic relationships of Theobromeae, we collected 280 samples from 45 species from herbarium specimens from 22 countries. We used genome sequencing techniques to investigate the genetic diversity of these specimens and to identify the traits associated with pathogen resistance and cadmium uptake and metabolism.

We are working with cocoa farmers and producers to share the knowledge that we are generating to help develop cocoa varieties that are pathogen resistant and that have low cadmium accumulation. These enhanced varieties will improve the marketability and profit margins of Colombian cocoa crops and increase the likelihood of cocoa being grown as a substitute for illicit crops.