Bananas have been struggling for a while now. Back in the early 90’s, bananas in Taiwan started to be infected by a deadly fungus called Fusarium Wilt Tropical Race 4. There is no known cure, and since the initial outbreak the fungus has spread, slowly at times, but largely unchecked. Infected plants have been quarantined, but this has been minimally effective, as any contaminated soil can spread it.
If you’re under 60 and living outside the tropics, chances are you’ve only ever seen one kind of banana – the Cavendish. It is the primary banana with mass commercial distribution, and unless something dramatic happens in the next few years, the days of the Cavendish banana may be coming to an end. And, there’s no replacement.
By 2013, TR4 had spread all over Asia and had been confirmed in both the Middle East and Africa. Then, just this week, TR4 took another step toward global annihilation of the banana, when it was confirmed in Colombia.
One of the most significant contributors to the spread of TR4 is the lack of genetic diversity in the bananas themselves. The Cavendish is a human-selected hybrid, like so many of our popular fruits and vegetables, but it is also sterile. The world’s crop is spread by grafting and by planting cuttings from mature plants. In other words, they are all genetically identical clones. (Or, perhaps they are more accurately described as multiple instances of the exact same plant).
This has all the makings of a banana disaster. We know just how serious this can be, because it’s happened before.
Prior to the 1950s, the most popular banana in the western hemisphere was the Gros Michel (aka”Big Mike”). This particular banana variety was found to be tough, resistant to rot, and easy to ship long distances. Its hardiness was a huge factor in the development of major banana plantations in Central America and the Caribbean, and companies like Chiquita cashed in, raising huge crops for the North American and European markets.
The Gros Michel crop was also a cloned plant – or arguably the SAME plant. So when Fusarium Wilt Tropical Race 1 (TR1, aka “Panama Disease”) appeared in the early 20th Century, it found thousands of acres of vulnerable, identical targets. While the economics of consistent monoculture made a lot of sense, it eliminated all genetic diversity in the banana. This made easy pickings for the fungus – a biological threat that could attack one, could attack them all. And attack, it did.
The entire banana industry was forced to change – but it didn’t change tactics, it just changed banana varieties. The replacement, our now-familiar Cavendish, was not as hardy, not as flavorful, but it WAS immune to TR1. So just before bananas were wiped out to the point where they ceased to be economically viable, we had a replacement.
(As an aside, if you’ve ever had old-fashioned, or just “old” banana-flavored candy and thought “this doesn’t really taste like banana”, it’s because it was made to taste like a different KIND of banana, the Gros Michel. Today’s bananas are different.)
But that was then, this is now. TR1 was actually mild, by fungal-epidemic standards. The Gros Michel still exists in Asia, and in isolated pockets that were never exposed. TR4, on the other hand, seems to be relentless, and much more easily spread.
The Cavendish banana crop is under attack by a biological enemy that is now active in both hemispheres, and we don’t yet have a replacement. No suitable banana varieties seem to possess any immunity to TR4, so what do we do when the crop is more costly to maintain than it is to sell?
Our options are limited:
1) Hope for some random, very-unlikely mutation among the billions of Cavendish clones that suddenly resists TR4, and upgrade the crop with that parent plant.
2) Get directly involved with the genome of the Cavendish, and engineer some resistance into it. (Yes, I’m talking GMO bananas – this is a perfectly viable approach that allows us to fast-forward through all the random mutations that don’t help and select the one that does. It’s genetically no different from the selection process that has allowed us to domesticate bananas, and apples, and grapes, etc. in the first place. GMO is not a bad thing – but the fact that many people reading this will have a visceral reaction to those 3 letters and think I’m crazy means that this option may not be a commercially viable one. It’s a shame… I like bananas.)
3) Abandon the banana mass-market, and go back to a genetically variant collection of “heirloom” bananas – like we do with tomatoes, potatoes, or apples. Given the limited range of climates where bananas can grow, this will likely make bananas a luxury item for much of the world. But on the plus side, it would force us to change the content of the monoculture plantations that exist today. There ARE lots of different edible banana varieties, as well as varieties of their cousins the plantains. Most don’t have a great shelf-life, or ship well, so unless you live where the bananas do, you’ve likely never seen them (and maybe never will).
The bottom line here is, bananas may not be easily available forever. The limitations of monoculture and cloning have come home to roost. While our favorite bananas may not go EXTINCT as a result of these infections, some varieties might – or they may be so vulnerable that the effort required to protect them isn’t worth the return.
It’s a catastrophe of biology, of genetics, and of economics. At least, if you like bananas.
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