New Cacao
Selections Offer Sweet Relief to Chocolate Growers
By Jim Core
October 1, 2002 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.
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