1. Skip to navigation
  2. Skip to content
  3. Skip to secondary content
  4. Skip to sidebar


  • More Sharing...

Saving the Source of Chocolate: Ghana Targets Killer Virus

Juliana Peasah

Ms. Juliana Peasah, a cocoa farmer in central Ghana, stands among the trees that are her family´s livelihood. (Photo credit: D. Kinley/IAEA)

Story Resources

Next to gold, cocoa trees - the source of chocolate - stand among Ghana´s treasures.

In the midst of a lush tropical forest near Tafo, Juliana Peasah carefully studies the leaves of her cocoa trees, searching for telltale signs of a killer disease.

"All my trees remain healthy and productive," explains Ms. Peasah, who owns about 5 hectares of land under cocoa cultivation. "It appears that we now have a variety that can stop the spread of this destructive virus."

This growing season (in late 2005) has gone well, with healthy harvests and no signs of the "swollen shoot" disease that has wreaked havoc on Ghana´s cocoa farmers for decades.

The hardier trees and healthier harvests are products of the country´s longstanding work with experts from the IAEA and UN Food and Agriculture Organization, who joined with national authorities to help protect and advance Ghana´s agricultural economy.

The Disease Problem

Almost 90% of the world´s cocoa production comes from smallholdings (under 5 hectares) like those of Ms. Peasah. An estimated 14 million people are employed in the cocoa industry worldwide; in Ghana alone the estimate is 3.2 million people, second highest in the world after Côte D´Ivoire.

Pests and diseases can cause up to 40% losses in cocoa production. Because of the Cocoa Swollen Shoot Virus (CSSV), some 200 million cocoa trees have been destroyed across Ghana in the last 50 years.

"CSSV is one of the most important factors limiting the production of cocoa in Ghana," explains Seth Osei Yaw, a senior technical officer working with the Cocoa Research Institute of Ghana (CRIG). "Attempts to control the disease have consumed massive manpower and resources that could otherwise have boosted productivity across the farming sector."

The disease severely affects the biological functions of the cocoa tree´s leaves, stems, and roots and generally causes seed-bearing pods to be smaller. Some virus isolates are so virulent that they cause defoliation and death of the tree.

Mutation Breeding for Disease Control

"Over the past decade, we have employed mutation breeding techniques to identify cocoa strains that have strong resistance to the virus," says Dr. M.R. Appiah, Executive Director of the CRIG. "Gamma-radiation induced mutant cocoa varieties are now growing on 25 farms across Ghana with no evidence of a resurgence of the disease."

Under carefully controlled conditions, buds of cocoa plants are bombarded with gamma radiation at the laboratories of the Ghana Atomic Energy Authority (GAEC) in Accra. The radiation causes mutations in the cell DNA and emergence of new plant strains with new disease resistant properties. The GAEC obtained this scientific capability through assistance from the IAEA´s technical cooperation arm and the joint programme the Agency runs with the UN Food and Agriculture Organization in Vienna, Austria.

"CSSV is the major problem disease affecting cocoa output in Ghana, Cameroon, Nigeria and increasingly in Côte D´Ivoire," explains CRIG´s Yaw Adu-Ampomah, one of the world´s leading experts on the disease.

"But by employing mutation breeding and getting the new variety planted in test fields, we have been able to short-cut the conventional plant breeding process by almost ten years. The field evidence is quite positive. We believe now that we’re beating this disease."

The successful genesis of this effort - climaxing in this promising mutant cocoa line being recommended for release as a new, high yielding and disease resistant variety - shows that mutation induction is a workable and efficient alternative to genetically modified organisms (GMOs).

Cocoa Production and Processing

The breakthrough will prove important to Ghana, which produced nearly 500 thousand tonnes of cocoa beans in 2003, or roughly 15% of the world´s supply, second only to Côte D´Ivoire, which produced more than 40% of total supply. Cocoa alone accounts for about 40% of Ghana´s total exports of about US$2 billion annually. Delivering revenues of $800 million, cocoa represents the country´s second largest export after gold.

Controlling CSSV could also make a major contribution to the country´s continuing economic renewal. Real economic growth has stayed within the range of 3-and-6% a year since the mid-1980s.

"Ghana stands out from most of the region as a country that has come back from disaster," says a recent economic survey in the Financial Times. "An ability to transform its farming base will determine whether the country can achieve sustainable growth beyond the support of donors."

The Financial Times survey explains, "Ghana still looks like the classic post-colonial African economy, depending on a few commodities and, more recently, expatriates remittances. Cocoa, gold and timber continue to account for three-quarters of exports."

But if the home compound of Juliana Peasah and her husband is any indication, rural Ghana is beginning to step out of it´s post-colonial straightjacket. Generous earnings from the coffee trade have transformed their home into a middle class lifestyle complete with electricity, running water, a television and stereo and even a new European car.

"We´re adding a new wing to our house," Juliana proudly explains. "Our earnings from cocoa are helping us build a more comfortable life."

-- Reported by David Kinley III, IAEA Division of Public Information.


Postscript: The IAEA - through its technical cooperation programme, scientific laboratories, and joint research with the UN Food and Agriculture Organization - has played a strong catalytic role in Ghana and other countries. Worldwide since the 1960s, plant breeders have won approval for more than 2300 mutant varieties of crops. Joint IAEA/FAO and technical cooperation projects fund, equip, and train scientists in crop production and improvement, as well as in soil science and other areas.

Next: Cocoa Connections: From African Forest to Belgian Boutique »