Entry: Dr. Lyndel Meinhardt, USDA/Agricultural Research Service

Cacao, also known by its scientific name, Theobroma cacao, or the ”food of the gods” is the source of cocoa and chocolate. Cacao originated millions of years ago in the upper regions of the Amazon River Basin in what are now Peru, Ecuador, Colombia and Brazil. This area is a vast region of tropical rain forest that is rapidly disappearing as the forest is cut down to exploit the wood and transform the region into pastureland and agricultural fields for growing crops such as soybeans. Cacao in its native habitat is in danger of being destroyed or at least its genetic variability, or germplasm, lost because of this human activity. Before this happens, the United States Department of Agriculture, Agricultural Research Service (ARS), intends to collect wild cacao plants from this region and preserve them in international collections so that they are not lost forever. For example, we know from historical records that the majority of disease resistant trees available today are descended from a few individual trees collected in Peru in the 1930s and 1940s. It is essential that we preserve more of the wild trees from their center of origin because we don’t know what important traits they may possess.

The only way to explore the region is by boat on the many rivers that feed the Amazon.

In July 2008, a team of researchers, including myself, went to Peru. A team composed of scientists from the Sustainable Perennial Crops Laboratory and the Systematic Mycology and Microbiology Laboratory at Beltsville, as well as members of the Instituto de Cultivos Tropicales (ICT), in Tarapoto, Peru, went on an expedition into the Peruvian Amazon rainforest to look for wild cacao trees. The expedition was funded by a Peruvian development project, INCARGRO and by the USDA. The purpose of this expedition was to collect wild trees, along with fungi that cause diseases that destroy cacao pods, as well as beneficial fungi that might be natural enemies of these fungal pathogens. We collected living samples from almost 200 trees in the wild. All of the materials collected, including grafted cuttings, are now preserved or are in collections that are growing at the ICT facilities in Tarapoto, Peru. The goal is to carefully evaluate all of these wild cacao plants to see if any possess traits that could be used to improve resistance to diseases or to give the chocolate industry new quality or flavor traits. The beneficial and pathogenic fungi will help us identify potential new biocontrol agents and to better understand the diseases that plague this crop.

The expedition team. Note the giant fan shaped cacao tree in the background. This was a single individual with multiple trees coming from a single root source.

Once desirable traits are identified from these collections in Peru, other scientists known as cacao plant breeders will take genes that regulate these good traits from the wild type trees and put them into varieties of cacao that can be cultivated in cacao farms. These trees will then have resistance to diseases and pests that destroy the cocoa crop and also other characteristics that will benefit the cocoa industry. Furthermore, if more funding becomes available, additional expeditions to other regions of the Amazon will be carried out to locate and preserve more of the wild cacao germplasm that might be beneficial to the future of the cocoa industry.

For a slide show with more photos of our most interesting expedition to the Amazon rainforest click on the following link.