The reason for sex

“The monoculture, the reliance on a single banana breed that makes all this possible — that makes the low margins work — also makes that fruit very susceptible to disruption,” said Dan Koeppel, who has traveled to 30 countries to sample varieties and wrote Banana: The Fate of the Fruit That Changed the World. “The biggest problem is disease.”

A lack of plant diversity isn’t unique to bananas. After a history in which more than 7,000 species were cultivated for human consumption, today just four crops — rice, wheat, corn and potatoes — are responsible for more than 60pc of human energy intake, the UN’s Food & Agriculture Organization estimates.
Losing breeds can be costly. When Gros Michel was killed off, the Cavendish proved immune to the fungus strain, though the bananas were smaller, less hardy and not as tasty, Koeppel said by phone from Los Angeles. It allowed the industry to recover, but the new variety required shipping in smaller boxes rather than big containers, he said. It took years to convert operations from farms to retailers.

Well it’s worse than this, because the Cavendish is a clone. Which is why the disease problem and why sex. Because that mixing of genes means not clones and thus one parasite won’t wipe out an entire species.

22 thoughts on “The reason for sex”

  1. After a history in which more than 7,000 species were cultivated for human consumption, today just four crops — rice, wheat, corn and potatoes — are responsible for more than 60pc of human energy intake, the UN’s Food & Agriculture Organization estimates.

    This is an odd framing. Yes, humans have cultivated numerous species, but since agriculture began, have relied mainly on one staple per society, usually a domesticated grass.

  2. Ref. Potatoes. The Irish potato famine was catastrophic because of the genetic uniformity. Seed potatoes were chopped up to multiply the crop, thereby ensuring a lack of diversity and no resistance to the blight.
    GM crops could suffer the same fate.

  3. They’re mixing up two different things; how many different breeds of bananas we use, and how many types of main crop. The reliance on rice, wheat, corn and potatoes doesn’t mean there aren’t lots of breeds of each being used, so avoiding the problem with bananas (not sure about rice, but there’s loads of different types of spuds in every supermarket).

  4. So Much for Subtlety

    Someone at the Tellie reads this blog. Because that is basically what I said on the last thread on bananas plus some from the Wikipedia page. I guess that the out break in Queensland is new as are efforts to contain it. Probably a press release.

    Although in fairness, most of what I said amounts to general knowledge. Not sure if that applies to the interns who seem to write most of the Telegraph’s content these days.

  5. Richard,
    “Not sure about rice”

    Allow me. Going into a shop here in Thailand and asking for, say, “ten kilos of rice” is like going into an English pub and asking for “a pint of beer”.

    Even tiny little backwaters will have a dozen to choose from.

  6. When they mentioned UN Food & Agriculture Organization, I thought this was going to be about why the UN must take over food production.

  7. That post was not as exciting as the title indicated it might be.

    JimW – a GM crop, all thing being equal, would be no more or less susceptible than the conventional variety from which it is derived. RR or whatever trait you’re trying to introduce shouldnt have any impact on disease susceptibility.

    Unless your comment is based on the fact that only a subset of available varieties have been modified (obviously), therefore there may be less diversity in the GM gene pool. That’s one of the better arguments in support of GM crops I have heard, as the solution would be to relax regs inhibiting gene tech in crops.

  8. re: monoculture
    Banana industry worth (wild guess) $20B
    And no plant breeders trying to make a better banana?

    re: Irish famine
    Poor choice of potato variety. You had peasant children with full bellies but still undernourished. When the blight hit it hit the worst variety, which also disrupted the lazy bedding cultivation of this inferior strain.

  9. So Much for Subtlety

    Bloke in Germany in Montenegro – “Weird to see SMFS appearing to advocate genetic diversity.”

    Why? I have always advocated genetic diversity. That is one of the many reasons why immigration is bad. One of the many genuine environmental problems in the world is McDonaldization. Indigenous species are being displaced by introduced species so that more and more, everywhere you go, you get the same species. The domestic cat and the European sparrow are pushing other species out all over the world. Nothing wrong with the cat and the sparrow but I would rather see some diversity in the world.

    And a world without red heads would be tragic. Yet that is the end result of replacing the European populations of the world with Somalis.

  10. BIF,

    > And no plant breeders trying to make a better banana?

    Tricky with bananas, as they’re not bred, they’re cloned. The different varieties must have come from somewhere, so yeah, it must be doable. But it’s a hell of a lot harder than, say, roses. Very good argument for GM there: could we make a cloning species fertile?

  11. Desert bananas have to be infertile, because no one wants to eat bananas with viable seeds in them. They’re infertile because their chromosomes are triploid.

    Plant breeders have tried to make a better banana, but it’s very hard work because yields are tiny – it takes an accident with the chromosomes for them to breed at all.

  12. Sq2, SJW

    Is a banana a mule as well as a clone? If so, just find the potential parents and play around with them.

    Odd coincidence, I was reading about cord grass. Comes as two species (N American and European) which cross to produce a mule, Spartina x townsendia.

    In the nineteenth century something went wrong with the cell division and instead of 62 chromosomes a plant got 124. This one was fertile and went on to become an invasive weed, where its forebears were pretty harmless.

    Probably counts as an entirely new species. Probably happens all the time at sea.

  13. No, not a mule. Seedless bananas are triploid – three of each chromosome rather than the usual two. (Whereas a mule is a mostly diploid hybrid with one or more unpaired chromosomes)

    It must be possible to get triploid bananas from diploid parents occasionally. But what you can’t easily do is pick out the ones you like and breed from them.

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