Friday, July 18, 2008

Are Banana Researchers Studying the Wrong Organism?

I just finished the very interesting book Banana: The Fate of the Fruit that Changed the World. It is amazing that a fruit that can only be grown in tropical regions, that must be shipped in refrigerated containers, and that must be eaten one week after making it to the store is the most commonly eaten fruit in the United States. But, it might not stay that way as Dan Koeppel writes in the NY Times:

Our great-grandparents grew up eating not the Cavendish but the Gros Michel banana, a variety that everyone agreed was tastier. But starting in the early 1900s, banana plantations were invaded by a fungus called Panama disease and vanished one by one. Forest would be cleared for new banana fields, and healthy fruit would grow there for a while, but eventually succumb.

By 1960, the Gros Michel was essentially extinct and the banana industry nearly bankrupt. It was saved at the last minute by the Cavendish, a Chinese variety that had been considered something close to junk: inferior in taste, easy to bruise (and therefore hard to ship) and too small to appeal to consumers. But it did resist the blight.

Over the past decade, however, a new, more virulent strain of Panama disease has begun to spread across the world, and this time the Cavendish is not immune. The fungus is expected to reach Latin America in 5 to 10 years, maybe 20. The big banana companies have been slow to finance efforts to find either a cure for the fungus or a banana that resists it. Nor has enough been done to aid efforts to diversify the world’s banana crop by preserving little-known varieties of the fruit that grow in Africa and Asia.
Researcher are trying to make new types of bananas that are resistant to Panama disease. The problem is that it is very difficult to create new breeds. As you probably have noticed, bananas have no seeds. The Gros Michel produces just one or two seeds for every ten thousand plants. In order to breed new bananas, you have to harvest lots of them just to find a couple of seeds. Then, after you get a few seeds and plant them to create a new breed, the odds are fairly good that its progeny will also have seeds which makes it unfit as a replacement. It takes a lot of time and effort to create new breeds of bananas.

I wonder though if the researchers aren't attacking the problem backwards. Instead of trying to breed a better banana, what if they tried to breed a more mild form of fungi that the banana could learn to live with? In this TED Talk, Paul Ewald explains how diseases such as cholera and malaria can be tamed rather than cured by changing their evolutionary path. Could the same thing be done with Panama disease and other fungi? If a milder strain of Panama disease could out compete the more vicious strain, then the current breeds of bananas could continue to supply us with our favorite breakfast cereal fruit.

Given how difficult it is to breed bananas, this might be an avenue worth exploring.

1 comment:

kara said...

Interesting post.
We love / need Bananas!

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