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New Cacao Selections Offer Sweet Relief to Chocolate Growers

The release by Agricultural Research Service scientists of nine new, high-yielding selections of Theobroma cacao, may offer new hope to the world's cacao growers--and to chocolate manufacturers and consumers everywhere.

Beans from T. cacao are the chief component of cocoa, cocoa butter and chocolate. But cacao trees are susceptible to many diseases that thrive in the tropical climates of South America and Africa.

The new selections--because they yield more beans than current varieties--could offset some disease losses. About 30 to 40 percent of the world's cacao production is lost each year, mostly through fungal diseases and pests such as black pod, witches' broom, frosty pod rot and the cocoa pod borer, according to the Chocolate Manufacturers Association.

At ARS' Tropical Agriculture Research Station (TARS) in Mayaguez, Puerto Rico, research horticulturist Heber Irizarry (now retired) and research plant physiologist Ricardo Goenaga selected cacao trees over a 10-year period. They removed scionwood suitable for grafting from hundreds of trees that consistently produced high yields. The candidates represented five parental families of T. cacao. The researchers then bud-grafted the scionwood onto a common rootstock known as EET-400. Trees grown from nine of the grafted selections were found to have higher yields than their parents.

Puerto Rico doesn't produce cacao on a commercial scale, but it has the ideal temperature and soil types to grow it. The U.S. Department of Agriculture is cooperating with several cacao-producing countries to address diseases, pests and other issues affecting the production of cacao beans. TARS researchers recently published findings that grafting was more effective than the common practice of using hybrid seed to develop higher-yielding cacao.

Genetic material of this release will be deposited in the National Plant Germplasm System in Mayaguez, where it will be available, in limited quantities, for worldwide distribution to growers--particularly to small landholders--and for research purposes. Increasing the diversity of the current genetic base could help researchers develop cultivars more resistant to disease, according to Goenaga, TARS research leader.

ARS is the USDA's chief scientific research agency.