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Dehybridizing Question

Posted by growneat (My Page) on
Fri, Oct 9, 09 at 20:24

I have been reading the posts about the 7 pound tomato and don't really understand about F1, F2, F3, F4 etc. The original Big Zac seed was an F1 hybrid seed and the seed has been grown so that now the seeds from the 7.18 seeds are F4. Is that F4 seed becoming similar to one of the parents of Big Zac or is it simply a new variety because each of the tomatoes selected to get to the F4 were based on tomato size only? I understand that you have to go out many generations to get a stable seed and my question really is do you end up with one of the parents or is it a new stabilized variety so to speak?


Follow-Up Postings:

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RE: Dehybridizing Question

you end up with a new variety


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RE: Dehybridizing Question

The F numbers refer to generation past the parents (Filial genrations). Parent 1 x Parent 2 = F1--children, F2 = grand children, F3 = great grandchildren.


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RE: Dehybridizing Question

Unless one of the parents skips town. Then you have B1, B2, B3, etc.


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RE: Dehybridizing Question

Lets say that you keep growing this seed and keep selecting for tomato size (big). Will it be fairly stable by F7? From what I have read it is about 83% stable now, meaning to me that if we grew 100 F4 seeds, 83 of them would be similar. Does that sound right?


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RE: Dehybridizing Question

Its reasonably stable at the F7

the second question the assumption isnt exactly right because of random chance. It is close if you are just considering one trait/one gene. Since size isnt exactly controlled by just one gene, one probably wouldnt see exactly that.


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RE: Dehybridizing Question

I don't have the room to grow 100 plants of a single selection, so my comment is from "single seed selection" point of view. Each year, I've grown between 2 and 4 vines of one particular cross and saved the seeds separately from the plant that gave the largest, smoothest fruit.

I was at F4 (vines grown from seeds saved from the same F3 plant of last season) with one particular tomato this summer and two vines that looked, acted and produced identically with regard to leaf shape, growth habit and production numbers still gave two sizes of fruit ... one large and smooth and the other medium size and smooth. Both tasted the same as far as I could tell. They grew side by side in a raised bed.


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RE: Dehybridizing Question

So you took the seeds from the larger one to grow next year?


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RE: Dehybridizing Question

Grownneat, I save the seeds from all the vines separately and lable each pack according to observation of individual vine/fruit characteristics.

I do this because Mulio told me that flavor, yield and size may change between F2 stage and F7 or F8 stability, and I want the opportunity to drop back and punt if necessary.

So far, with this particular cross, it's been a steady improvement with regard to productivity and smoothness of the fruit with the flavor not really varying between the larger fruited vines and the less large.

So yes, I continue to plant seeds from the vine that produces the larger tomatoes each year.

Single seed selection and growing only 2 - 4 vines per year certainly isn't the optimum process. It's just all I can fit in and still try out several other varieties in the same year with my limited space.


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RE: Dehybridizing Question

So, and correct me if I am wrong, if you grew the seed from the larger tomato and got small tomatoes instead of the large one you anticipated, you would drop back and grow the seed that gave you the large smooth tomato in the first place? And by the time you got out to F7 or F8 you would either have something you liked or not and if not you would be starting all over again with some new F1 seed?


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RE: Dehybridizing Question

Yes, pretty much like that.

But, if at the end like at F6 or F7 I had a really good tasting, medium size, smooth tomato that produced a heap over the entire season, then that would be just fine too.

It's like when I crossed Brandywine x Neves Azorean Red, in the F3 I got some saladette and large saladette sizes ... 2 were plum shaped and two were round ... out of 10 plants this summer. Weird, I know. But oh so tasty. And that's just fine with me even though they are very small compared to the F2 tomato the seeds came from.


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RE: Dehybridizing Question

My guess is that you have been reading the posts about the 7 pound tomato and that it was grown from an F3 Big Zac? The question is, if you were to be able to get some of the seeds involved, would you rather have seeds from the 5.58 pound tomato that ultimately grew the 7 pounder or would you rather have seeds from the 7 pounder? I am thinking based on what I know now that the answer would be the 5 pound tomato since it is more proven. I have a friend that grew the 5 pounder's seeds but he did not get anything huge though he did get one tomato weighing 3.8 pounds. Where would the seeds from that tomato rank amoung your choices? To clarify, would you rather have seeds from the 5 pound tomato (F3) or from the 7 pounder(F4) and if you could not get those would the almost 4 pound tomato(a different F4) from the 5 pound seed be of interest to you? I hope I have not confused you and that I have not worn out my welcome with these questions.


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RE: Dehybridizing Question

I would rather have 16 seeds from the 5.58 pound tomato that are sibling seeds to the seed that grew the 7-pounder than to have 4 seeds from the 7-pounder ... or 24 of the previous gen. vs. 6 seeds from the current gen., etc.

Then of course I'd love to have a few seeds from the proven 7-pounder, too. Right? Never sure exactly whatcha gonna get when it's still unstable. Seems like your friend is on to something though.

But if you're growing purely for size, you should get a few of whatever is available to you and plant them out early enough to take advantage of the distorted blossoms that cooler spring and early summer weather will afford you.

I'd even consider experimentally giving the plants an occasional blast from a CO++ charged fire extinguisher to see if it would cause distorted, fused blooms or something.


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RE: Dehybridizing Question

Be careful what you say...Carolyn might be listening. LOL. I have a lot of respect for Carolyn so don't get that comment wrong.


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RE: Dehybridizing Question

I'm going to be a test of your theory next year. I saved seed from my Brandy Boy F6 this year, so next year will be F7. Each year I grow F1 and the latest generation so that I can compare. I plant them at opposite ends of my tomato row to discourage cross polination. So far, the taste, size, shape, etc., are exactly like the F1's.

Not sure if I agree with your discussion about size. I have seen 2 seeds from the same commercial pack produce greatly different size and shape fruit. I think it's more a function of weather and amount of sun, water and food. This year that was especially true of Rutgers.

John A


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