Scarce-Banana Scare—But don’t kiss that banana good-bye yet

Headlines have been blaring that the banana will be extinct within 10 years but crop specialists say that’s not likely. The furor has called attention, however, to a problem of worldwide banana supply and to the possibility that we’ll be peeling things a little different in 2013.

The fuss started with the Jan. 18 New Scientist cover proclaiming, “The world’s favourite fruit is about to disappear,” and a story featuring Emile Frison, the director of the International Network for the Improvement of Banana and Plantain in Montpellier, France. The notion sped around the world via stories in newspapers from Uganda’s Kampala Monitor to the Boston Globe.

Saying that the banana is likely to disappear is overstating the case, says Frison. What he was actually talking about, he told Science News, was the trouble with banana breeding in general and the particular plight of a beauty called Cavendish. This banana variety yields abundant crops, ripens uniformly on command, turns a lovely yellow, and tastes exactly the way most imported-banana eaters expect the fruit to taste. This is the top banana on supermarket shelves in Europe and North America.

Cavendish’s history has now come back to haunt it. It took over the international banana trade some 50 years ago, when a strain of the dreaded fungal wilt called Panama disease started killing the previous export star, a banana called Gros Michel. The fungus grows into and chokes a plant’s water vessels. Leaves brown from the margins, and the plants wilt and die. The fungus lurks in the soil, so once a field is infected, the disease is very hard to control. Originally, Panama disease could knock out Cavendish bananas at the chilly fringes of their range but not in the tropical heart of banana territory.

Now a new fungal strain, called race 4 of Panama disease, has struck in Southeast Asia, and this one can kill Cavendish bananas in the tropics. If the disease sweeps through other big banana areas, such as top export producers Ecuador, Costa Rica, and Colombia, the Cavendish reign on supermarket shelves could be ending.

That’s hardly the end of the banana though, says Frison. The export market accounts for only 13 percent of bananas grown worldwide. Farmers grow the rest of bananas for consumption within their own country and are more likely to raise local types. So far, researchers have catalogued some 500 kinds of bananas. “Let me reassure you, all bananas are not going to go extinct in 10 years’ time,” Frison says.

When news accounts exaggerated the gloom of his statement, Frison says, “originally, I was quite upset.” He’s changed his mind though, because he believes the story has raised public awareness of a serious problem. According to Frison, the possible need for a replacement supermarket variety shrinks as a problem beside the towering needs for better bananas for small farmers who depend on the crop for subsistence.

Hundreds of millions of people face malnourishment because of banana diseases, says Frison. In the developing-world tropics, bananas rank fourth as a staple crop after rice, wheat, and maize. Uganda represents the extreme case, where people eat an average of some 200 kilograms of bananas a year. In some parts of the country, the word for banana is also the word for food.

Yet in some places in the tropics, such as West Africa, banana yields have dropped by half in the past 3 decades because of rising banana maladies. A disease called black Sigatoka, for example, attacks leaves, stunts plants, and shrinks harvests. What’s needed, Frison says, is public-sector investment in new varieties of bananas that can resist diseases.

What the scare accounts did get right, Frison and other specialists say, is the extreme difficulty of breeding new banana varieties for either supermarket sales or subsistence. Because many kinds of cultivated bananas have lost the ability to make seeds, there’s no way to cross-pollinate some plants in a breeding program. Farmers propagate banana plants via cuttings, and breeders struggle to foster what limited fertility remains. Frison says he doesn’t know of anyone who’s managed to get a seed for a Cavendish variety. Some other varieties–if researchers find just the right combination of parents–will yield seeds. In other cases, researchers go through hundreds of fruits to rescue a few developing seeds before the plants spontaneously abort them. Frison is leading a project to sequence the banana genome and hopes that genetic engineering will boost the prospects for making new varieties of this difficult fruit.

Some breeding programs have labored for 80 years and are only now producing banana varieties that might catch on, says Sharon Hamill, senior scientist at the banana collection in Maroochy Research Station in Queensland, Australia.

Banana-disease specialist Randy Ploetz of the University of Florida in Gainesville agrees with Frison that extinction of bananas is “not likely.” Yet he acknowledges that Panama disease would be a disaster if it reached Cavendish bananas in South America’s banana basket. “There are no chemicals that work” against the fungus, says Ploetz. For now, he’s hoping that strict import controls will keep the disease far away from the Western Hemisphere. Australia, too, is counting on strict quarantines, says Tony Heidrich of the Australian Banana Growers Council in Brisbane.

In the meantime, Ploetz advocates that banana consumers get a little adventurous. U.S. markets, particularly those with Hispanic customers, now often carry several snack and cooking varieties. “There are all these other bananas out there–they taste great. You should try some,” he says.

Hamill lists some of the promising ones she’s seen: a small, sweet one called Goldfingers; the Red Decca, which has creamy insides and a red skin; and one called Pacific Plantain, which grows to about twice the size of a typical supermarket banana.

Is she worried about extinction of the banana? “Not really,” she says. Banana breeding certainly is difficult, but she has 400 varieties of the plant in test tubes. What she sees in 10 or 20 years, she says, is not extinction at all, but “more diversity.”

Susan Milius

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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