How Would You Grow the World's Biggest Potato?

Reports of a record-breaking spud from Lebanon may turn out to be half-baked















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UGLY BUT SWEET Lebanese farmer Khalil Semhat holds a giant potato in the southern Lebanese city of Tyre on December 6, 2008. The farmer couldn't believe his peeled eyes when he discovered he had grown a massive potato weighing 11.3 kilos (24.9 pounds), he said, adding that he now hopes to enter the Guinness World Records book. Image: Newscom

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On Tuesday, the BBC decried the end of the 10-year reign of  the eight-pound Manx Potato as the world's heaviest. Its record had apparently been uprooted by a 25-pound spud from Lebanon.  In photos, circulated across the Internet, farmer Khalil Semhat hoists his misshapen tuber up like a proud father.

"I didn't use any chemicals at all," Semhat proclaimed to Agence France-Presse. "I've been working the land since I was a boy, and it's the first time I've seen anything like it."

The Manx's owner, Nigel Kermode of the Isle of Man, reluctantly conceded the crown: "We're still a world champion – we'll call it the second biggest potato in the world."  His decade-old  tater was reportedly "grey and brown" and hadn't been on display for quite a while.

But experts contacted by Scientific American say that Kermode has nothing to concede.  This is all a case of mistaken identity. Michigan State University potato expert David Douches says the vegetable in Semhat's hands looks an awful lot like a sweet potato – a crop more closely related to morning glory flowers than to hash browns. 

To settle the matter, we decided to talk to Kenneth Pecota, a plant breeder who has spent 15 years working on roots as part of North Carolina State University's (NCSU) Potato and Sweetpotato Breeding and Genetics Program.

[The following is an edited transcript]

What type of vegetable is Semhat holding in the photo?

It sure looks like a sweet potato to me.  Everything about it, the skin color, the skin peeling off with the white underneath -- that's very common in big, sweet potatoes.  When the sweet potatoes get big like that, that cracking is extremely common.  You also have the veins, which are little fibrous roots growing under the surface, that's very common with sweet potatoes as well.  We see stuff like that all the time at NCSU.

I don’t think he has a potato, I think he has a sweet potato.  I'm guessing that there was confusion somewhere in the translation. It's probably a language thing.

Well, perhaps it's a record-breaking sweet potato?

No, not even close.  We had one that size this year, and we're not even trying to grow them big.  Sweet potatoes are perennial and they'll just keep growing.  If he's got a long growing season in Lebanon, which I'm guessing he does, or if you space them out and give them optimal growing conditions -- 20, 30- plus pounds is not even uncommon.  It's big but it's not out of the realm.

I think there was a person that made the news, Janice Bohac, who used to be the sweet potato breeder at the USDA. She was toying around with a 41-pound sweet potato for ethanol production.

His is not even near the record.  [Though] it might be up for the ugliest one!

[According to the 2007 Guinness World Records, the world's largest sweet potato was 81 pounds.]

What's the difference between a potato and a sweet potato?

A sweet potato is a modified root and a potato is a modified stem and, therefore, a [true] tuber.  One of the big differences is that the sweet potato is a perennial and they continue to grow indefinitely while a potato has a predetermined length of season after which the plant will senesce and you're done, which is probably why your biggest potato is in the eight-pound range.



5 Comments

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  1. 1. gs_chandy 08:42 AM 12/10/08

    It's a sweet potato. I know - I've grown both potatoes and sweet potatoes.

    GSC

    Reply | Report Abuse | Link to this
  2. 2. ZenaV 04:11 PM 12/10/08

    I cook and eat both kinds of potatos and that looks like a yam to me!

    Reply | Report Abuse | Link to this
  3. 3. just me 04:46 PM 12/10/08

    It all has to do with the fact that in Arabic, sweet potato is called "batata" (there's no "p" in Arabic, so "p" is pronounced "b")... The guy holds a big batata but not a potato.

    Reply | Report Abuse | Link to this
  4. 4. camote 11:55 AM 12/11/08

    For those who enjoy looking at pictures of big sweet potatoes, I have a collection of Chinese giants: http://nlp.cs.jhu.edu/~edrabek/camotes/giants.html

    Reply | Report Abuse | Link to this
  5. 5. JBOHAC 08:55 AM 12/12/08

    I can confirm this is a large sweetpotato - the type that has been bred for high yield and high starch content.

    Anyone interested in contacting me about high yielding sweetpotatoes for fuel ethanol that can put corn "on its ear" can reach me at my e-mail

    angeloakey@aol.com

    Janice Ryan-Bohac, PhD
    Plant Breeder
    CAREnergy

    Reply | Report Abuse | Link to this
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