Cover Image: October 2010 Scientific American Magazine See Inside

Death and Chocolate: Disease Threatens to Devastate Global Cocoa Supply

A blight is threatening the world's cocoa supply. Will genetic intervention save our desserts?















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Pod squad: Scientists are racing to breed resistance in cacao trees to a deadly disease. Image: Getty Images

In a rare tale of technology, bio­terrorism and chocolate, scientists are racing to sequence the cacao tree genome. They fear that without the genome in hand they will be unable to stop the spread of two virulent pathogens that threaten to devastate the world’s cocoa crop.

Cacao trees were first domesticated more then 1,500 years ago by Mayans living in what is now Central America, but fungal diseases such as witch’s broom and frosty pod have largely chased the bean out of its native habitat. The great worry is that one of these diseases will cross the Atlantic Ocean to West Africa, where 70 percent of the crop is now produced. Cacao trees in West Africa have no resistance to the pathogens, which form spores and spread via the wind, careless farmers and, in at least one case, bioterrorists. Scientists say that just a few infected pods would lead to the loss of one third of total global production.

One way to forestall such a crash is to breed plants that are resistant to infection. Scientists identify naturally resistant plants, artificially pollinate them, then test their offspring. This is a slow process, and having the cacao genome in hand would speed things up. Scientists would be able to identify the sections of DNA that confer increased resistance and select the best trees to breed. “It’s expensive work,” says Randy C. Ploetz, a plant pathologist at the University of Florida, “but once you have a genetic sequence, it makes that work a lot easier.”

Scientists expect to release a first draft of the cacao genome by the end of the year; identifying the genetic sites responsible for resistance will take a few years more. In the meantime, producers in Côte d’Ivoire and Ghana have instituted strict quarantines to help protect their crops.



This article was originally published with the title Death and Chocolate.



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4 Comments

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  1. 1. Wayne Williamson 08:22 PM 9/24/10

    this sucks...almost everyone loves chocolate....i also thought that most of the chocolate comes from south america not africa......

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  2. 2. jimhenson 05:04 PM 9/27/10

    eat your chocolates while you still can, before they find a way to make a chocolate candy bar $10 each. Buy chocolate as investment and keep it in your commodity portfolio, consider oil was still $20 per barrel less then 6 years ago !

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  3. 3. verdai 05:11 PM 9/27/10

    No lie.

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  4. 4. minna in reply to jimhenson 03:52 AM 10/3/10

    great comment!!!! ^_^

    Reply | Report Abuse | Link to this
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