Bananas; an endangered fruit
2003-01-16 19:26
London - Fungal disease could finish off the banana within 10 years, with dire consequences for half a billion people in Africa and Asia for whom it is a staple, according to a French research scientist writing in the New Scientist journal Thursday.
Emile Frison, head of the International Network for the Improvement of Banana and Plantain (INIBAP) in Montpellier, said two diseases, black Sigatoka and Panama, threatened the future of the world's most popular fruit.
Bananas are sterile mutants of inedible natural plants, making it difficult to create new varieties resistant to the diseases by natural methods. Genetic engineering could thus be the answer.
In the 1950's the dominant Gros Michel banana was wiped out by Panama disease, caused by a soil fungus. Now its successor, the Cavendish, is threatened by globally by black Sigatoka, another fungal disease.
"In some ways, the banana today resembles the potato before blight brought famine to Ireland a century and a half ago," Frison wrote.
"As soon as you bring in a new fungicide, they develop resistance ... One thing we can be sure of is that the Sigatoka won't lose in this battle," he said.
Panama disease is making a comeback in a new form which has attacked the Cavendish. So far it has reached South Africa, Australia and much of Asia, and unlike black Sigatoka, cannot be controlled by chemical fungicides.
Once it reached the large western hemisphere plantations, the banana business would be doomed, Frison said.
Almost all existing edible varieties are susceptible to the two fungal diseases, and a hybrid produced by laboriously searching for genetic accidents among thousands of sterile edible fruit turned out to taste more like an apple than a banana.
Frison believes genetic engineering may be the only answer, and a global consortium of scientists announced plans to sequence the genetic blueprint of the banana within five years, focusing on wild bananas resistant to black Sigatoka.
But the large producers refused to get involved, because of the cost and fears that consumers will not accept a GM banana.
Frison also stressed he was more interested in preserving the varieties used as a staple in parts of Africa than in those found in Western supermarkets.
Half a billion people in Asia and Africa depend on bananas. In Uganda, bananas are grown on a third of all cultivated land, and per capita consumption is 50 times that in Britain.
Experts believe the first edible banana was grown about 1 000 years ago in South East Asia, making it one of the oldest crops.
The wild banana, a giant jungle fruit called Musa acuminata, contains a mass of hard seeds that make it virtually inedible. Edible bananas are mutant freaks, rare in the wild, that have no seeds and are sterile.
Stone age plant breeders are thought to have cultivated the mutants by replanting cuttings from their stems. The descendants of the original cuttings are what we eat today, and each variety of modern banana has come down almost unchanged from an individual sterile forest mutant.
"Each is a virtual clone, almost devoid of genetic diversity, and that uniformity makes it ripe for disease like no other crop on earth," according to Frison's article in the New Scientist.
Honduran scientists, who peeled and sieved 400 tonnes of bananas to find 15 seeds for breeding, may have found a fungus-resistant variety which could be grown organically.
- SAPA