They're certainly among the most convenient fruits. Bananas are compact, tidy, bundles of potassium and deliciousness. And when we says "bananas," what we really mean are Cavendish bananas, an edible, cultivated subgroup of the fruit. Ninety-nine percent of the bananas sold in the world are seedless Cavendish bananas, although in the wild there are over a thousand strains of bananas, many of which are unsuitable for eating. Unfortunately, Cavendish bananas are about to go extinct.
Cavendish bananas are pretty much genetically identical — they're all sterile clones from the fruit of a single English tree, grown in 1834 by William Cavendish, the 6th Duke of Devonshire, in his greenhouse. As such, they're all vulnerable to the same threats. What's killing them now is a soil-borne fungus, Fusarium oxysporum f.sp. cubense (Foc), also known as Fusarium Wilt Tropical Race 4 (TR4). It kills bananas by infecting its root and vascular system, rendering it unable to take in critical minerals and water.
TR4 first began ruining Cavendish bananas in Malaysia and Indonesia around 1990 and has since made its way through Southeast Asia and to the Middle East and Africa. Last year, it reached Latin America, the world's main source of bananas.
Growers are doing what they can to beat back T4's advance—including taking acre to use only untainted planting materials so as to avoid spreading T4 via soil contamination—and Australia has shown some success in slowing down the assault. However, these are stopgap efforts that are ultimately unlikely to save the Cavendish.
This is not the banana industry's first encounter with this fungus. Up to the 1960s, the world's most popular edible banana was the Gros Michel, or "Big Mike," variety. To meet worldwide demand, growers got into the Gros Michel monoculture business big-time, with thousands of tropical-forest hectares converted into massive plantations growing these bananas.
What spelled doom for the Gros Michel banana was, yes, Fusarium oxysporum — the disease it caused was known as "Fusarium Wilt," or "Panama Wilt." It was the T1 version of today's T4, and it largely wiped out the Gros Michel banana, nearly taking the entire banana industry down with it. (You can still find a Gros Michel banana, but it's not easy.)
The Cavendish didn't quite have Gros Michel's rich taste, but it wasn't vulnerable to T1, and so it took the place of the Gros Michel as the world's main edible banana.
Journalist source:Berman, R. (2020, JULY 2020). BIG THINK. Retrieved from https://bigthink.com/surprising-science/cavendish-bananas-doomed?rebelltitem=1#rebelltitem1