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Old November 20, 2017   #1
Nan_PA_6b
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Default How to get the taste.

Hi all,

I'm trying to develop a tomato for my mother. She tasted a Hardin's Miniature tomato & said "Now if only they could get that taste in a full-sized tomato!" So I'm trying to make one.

I have a cross of Anna Maria's Heart x Hardin's Miniature. The F1's are growing now. All I really need from AMH is the full sized plant and fruit. After that, it's just selecting for HM's taste. I don't care about fruit color or shape.

Genotypes:
AMH = large fruit, large plant, indeterminate.
HM = small fruit, two sets of dwarf genes, determinate habit, everbearing, perfect taste.

I'm guessing I should do this:

F2: select for large plant & fruit. Cross with HM to get a new F1. Select for large plant.
New F2: select for large plant & fruit. Cross with HM to get new F1. Select for large plant.
Newest F2: select for large plant & fruit. Cross with HM to get new F1.Select for large plant.

etc, till I get something that tastes like HM. Then, stabilize.

I know there will be a lot of interesting stuff popping up along the way and I intend to pursue some of them later, but I was hoping to get this cross done while my mother is still young enough to garden. (She's a spry 87.)

I can grow under lights in winter, and I don't believe I'll need too many of any generation at first since I'm only selecting for large fruit and plant. And the large plant part can be selected during the seedling stage.

Does my plan sound like the best way to go? Advice?

TIA,
Nan

Last edited by Nan_PA_6b; November 20, 2017 at 12:14 PM.
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Old November 20, 2017   #2
Salsacharley
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Why not incorporate the dwarf traits in a large tomato with HM taste? I wouldn't exclude dwarfs that meet your other trait requirements.
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Old November 20, 2017   #3
joseph
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Seems to me, like taste should be the primary selection criteria in every generation after the F1.

The way that I would approach this project, would be to get seed from the F1, and then plant about 100 F2 plants, and select among them for plants that have both the taste and the size that you are looking for. That way, the project will be essentially done in one growing season.

Don't have the room? Place the plants an inch apart . That will l fit 100 of them into an 8 feet row.
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Old November 20, 2017   #4
KarenO
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agree with Joseph. If taste is your only selection criteria then grow out a bunch of the F2 of your cross, (for me though, as many as you can grow reasonably properly, enlisting friends for extra plants if possible )taste them at maturity and save seeds from the one your mom loves the most. there is bound to be a good one in the F2.
It doesn't have to be so complicated whatsoever if you only have one selection criteria. If among Joseph's suggested 100 plants you don't find one you like, no amount of backcrossing will fix that imo. It is better to make a new cross in my opinion than backcross trying to get something back that wasn't there to begin with. Leave that to the pros working on disease resistance etc with hundreds of plants. Remember also, every time you back cross it's a new cross and stabilization starts over at f2.
KarenO

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Old November 20, 2017   #5
bower
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Yep. Every time you cross back to HM you are stacking up the recessives for dwarf size and small fruit, making it more difficult to find what you're seeking.

You should be able to find something promising in the F2, but if you don't, I would suggest trying a different parent for "full size tomato" instead of trying to force it by backcrossing. Why a different parent? Because IMO taste genetics are extremely diverse and complex (many many genes involved), and if results are not as expected, there may be issues such as linkage and epistasis affecting this parent combination. You can also try crossing the F1 or F2 to a third parent, as a workaround for epistasis. Or even better, you could start by crossing HM to two different 'large fruit' parents. Then you have two shots at the HM flavor genes by crossing the F2's.

As KarenO pointed out, each time you make a new cross you are back at the F1 stage and seven generations from stable. But honestly you are better off to make the new cross one way or another, if you're not finding that key trait that you wanted to carry forward. Or alternatively, just keep growing out more and more F2's until you find it.

Large size is one of the harder traits to recover, btw. So do expect to grow lots of F2's to find a big one with the taste you desired.
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Old November 20, 2017   #6
Nan_PA_6b
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Salsacharley, you are right. I am able to utilize a large-fruited dwarf for my purposes. I shall include them as well.

Everybody else: I keep hearing that taste is a combination of so many different chemicals and variables; I assumed many different genes contribute to the flavor of a tomato. You really think that I could find everything I want in the F2? In that case, I'll just collect up a ton of F2 seed and grow 'em out until I find the Goldilocks one, then begin stabilizing.

Shoot, this 'mater makin' is easy!

Thank you, everyone!

Nan
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Old November 22, 2017   #7
Nan_PA_6b
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OK, I did the math of a huge square chart (Pareesi squares?) and worked out the odds. (I enjoy the math). Also juggled the numbers and figure I can evaluate 55 plants this summer, if I use a shoe horn & a cooperative mother.

Theoretically, on the average, from 55 plants I would get 13 large-fruited (large or dwarf) plants. More if I'm lucky, less if I'm not. That does not allow for small fruited varieties to live long enough to taste the fruit. Just evaluate for fruit size, rip 'em out if it's small, and re-plant late seedlings in their place.

I'm so psyched!
Nan
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Old November 22, 2017   #8
bower
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Well I hope you do get 13.
Frogsleap posted a very interesting blog some time ago, about the skewed ratio of small vs large fruit in crosses of small X large. His findings, you actually needed about ten plants to find one large fruited, because the ratio is skewed towards small.
I have to say, my own results have pretty much agreed with that observation.
So you may only get five out of 55 that are close to the size of the large parent.
OTOH you should get lots of intermediate sizes as well, and maybe a lesser amount of "bigger" than HM is an easier target that would satisfy your mum as well.
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Old November 22, 2017   #9
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(Great thread - learning a lot. Jeff)
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Old November 22, 2017   #10
Nan_PA_6b
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Thanks for the heads up, Bower!

By "large fruit" I simply mean larger than HM. In the F2, I'll be happy with 2-4 oz. The bigger the better, though.

It's encouraging that I should still average 5 out of 55. Five is better than zero, which is what I have now. Five would let me grow out 11 of each F3.

Nan
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