Seedless: how is it done?

[Fat Guy]

Would somebody please explain to me how seedless fruit is accomplished?

[Kerry Beal]

It's all in the breeding!!

See here for the Wiki version.

[Hiroyuki]

Gibberellin is used to make grapes seedless.

My father grows several varieties of grapes in his vineyards. He puts gibberellin solution in a cup, and dips each and every bunch of grapes in it for a few seconds. He has to do the dipping twice to make the grapes seedless.

[BarbaraY]

I have never heard of Gibberellin. Interesting because I have grapes, Thompson Seedless, that are naturally seedless. They must be propagated by cuttings.

[russ parsons]

i'm sure hiroyuki's dad used giberellic acid, but not for seedless--it's a growth promoter and makes the grapes bigger (thompson's are naturally pretty small ... in fact, there's a new popularity for untreated thompsons, which are sold as "naturals").

Seedlessness in fruit (says mr. how to pick a peach), can come about in several ways. one is an imbalance in chromosomes (think bananas and navel oranges). some fruits can only be pollinated outside their species; grow them in isolation and they'll be seedless (think clementines and other tangerines); some are grown in greenhouses that prevent bees or other pollinators from entering (think cucumbers). Some seem to be seedless, but aren't really. thompson seedless grapes are among these--there actually are seeds, but they're extremely tiny and never mature.

[melkor]

And strangest of all is the navel orange - all navel oranges everywhere can be traced back to one mutated tree.

[russ parsons]

And strangest of all is the navel orange - all navel oranges everywhere can be traced back to one mutated tree.

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actually, there's a lot more of that than you might expect. "sports", or spontaneous genetic mutations, account for a lot of the primal varietals. in addition to navel oranges (a 19th century Brazilian sport), so is the Cara Cara (a sport found in venezuela in the 70s). so is the hass avocado--the original tree (or a tree from wood from the original tree) is still standing in southern california. And so is the red delicious apple--the story goes that the farmer kept trying to kill the sport in his orchard and when it wouldn't die, he decided to let it grow to harvest.

of course all of these have been "improved" by breeders over the years.

[Kouign Aman]

Grower gets a mutation, propagates mutation via cuttings & sometimes grafting. There really is a 'mother of all..' for some of these, as russ parsons describes. Same technology that creates a tree which produces multiple varieties of a fruit.

[russ parsons]

and in some cases, the mutations are caused purposely. this is called breeding. there is a plaque in a garden in the loire that commemorates the birthplace of the comice pear. personally, i think it should be a statue.

[Kouign Aman]

breeding for seedless / small seeded fruit?

I must do more reading, because on the face of it, thats like saying childlessness is hereditary - worth a happy chuckle. But, being as plants are what they are, it might well be possible, since a similar effect is obtained by breeding for more fruit to the same size seed.

[russ parsons]

sadly, seedlessness is one of the most valued traits in my fruits these days. makes 'em better snacks.

[Hiroyuki]

i'm sure hiroyuki's dad used giberellic acid, but not for seedless--it's a growth promoter and makes the grapes bigger (thompson's are naturally pretty small ... in fact, there's a new popularity for untreated thompsons, which are sold as "naturals").

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I'm pretty sure that this is a common practice in Japan to make grapes seedless.

Click here (Japanese only), scroll down to the 9th photo. You can see how a bunch of grapes is dipped in a cup with gibberellin in it.

[russ parsons]

unfortunately, i can't read japanese, but here is the wiki entry on gibberellins. there is a long list of things they are used for, but producing seedlessness is not one of them (in fact, it says it is used for seed propagation, which i hadn't heard).

[sanrensho]

I'm no expert (nor even a novice) on this subject, but here's a link to an English summary of one Japanese study on the use of gibberillin to induce seedlessness in grapes:

http://ci.nii.ac.jp/naid/110004788974/en/

[russ parsons]

good find. i stand corrected. i have never heard of that being done in this country.

[Hiroyuki]

good find. i stand corrected. i have never heard of that being done in this country.

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It's such a meticulous procedure, so maybe it's not practiced outside of Japan.

Thanks for the link, sanrensho. You are so fast!

Now I think it's time to get back to the original question. I know there is a seedless variety of watermelon, but it's not popular in Japan because it's expensive and smaller than regular ones.

[Adam Balic]

I have never heard of Gibberellin. Interesting because I have grapes, Thompson Seedless, that are naturally seedless. They must be propagated by cuttings.

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Grape vines are cultivated from cuttings, that is how they remain the same decade after decade. Ditto roses, fruit trees and any other plant that you want to remain gentically pure (with the exception of mutations occuring).

"Thompson Seedless" is the common USA name for the seedless Sultana grape. To get large elongated berries they are commonly treated with giberellic acid (which is naturally produced by fertile seeds and normally results in berry grouth), without treatment the berries are very small. In Australia the smaller untreated grapes tend to get called "sultana", where as the larger treated grapes are called "Thompson Seedless", but they are the same variety.

Manyseedless fruit are triploids, this can occur naturally (eg. seedless banana) or be bred. Essentially if you cross fertile diploid and tretraploid parents you get sterile triploid progeny. The triploids tend to be bigger also.

You can also have normal chromosome plants with genetic issues, which results in a block in seed development.