idea/ project breeding tomatoes?
 

Hey guys, Im new here at tomatoville, Seems like a great place and everytime I go on here I cant get off it.

Anyways, I am interested in breeding some tomatoes or something interesting. I was wondering of doing something along the lines of the dwarf project. Could I cross a large tomato with a tiny tim to hopefully one day have a small frame plant with larger tomatoes?
I realize its probably far fetched and if it was that easy it would have been done by now.
I have experience growing vegetables and also I am a young grain farmer on my second season. I am looking for something advanced to work on.

That's not impossible at all. Though you'd probably need to back-cross to the larger fruited parent at F1 and then grow out LOTS of F2's and 3's to re-capture the smaller plant. It's hard to overcome cherry-size genes. Hopefully ChrisK will chime in here, he's the MAN when it comes to micro tomatoes.

IMO, your objectives could be better met by combining the dwarf gene with very large fruit such as with Perth Pride X Red Mortgage Lifter or Neves Azorean Red. The micro varieties such as Tiny Tim have less capacity to support large fruit because of the plant structure.

okay thanks for the reassurance. I already have the tiny tim seeds but I will buy some open pollinated beefsteak seed. I think it would be a cool project to do and hopefully have some sort of positive outcome.

fusion_power I just saw your post after I put mine up. yeah I understand what you are saying I will into that if it is more realistic. Thank you

Tiny Tim has two recessive dwarfing genes. In your hypothetical cross it is convenient to use the TT plant as the mother, as any selfed seeds will be tiny and any F1s will grow huge(normal) sized plants. Isolate this plant from others and save every seed it produces.

In the F2 generation, 1/16 of the plants will be micro (having two dwarfing genes in the homozygous state) and 6/16 of the plants will be dwarf (having one or the other dwarfing genes in the homozygous state). You can identify which plants are normal/dwarf/micro in the seedling stage with some practice, so you don't even have to grow them to full size. You can screen through many seeds and only grow the size you want.

Don't even bother to grow out F3s unless you saved seeds from a dwarf/micro F2. If the F2 you save seeds from is normal sized, it could have one copy of both, one, or neither of the dwarfing genes. If you luck out and it carries one copy of -both- dwarfing genes, then the seeds produced will have the same pattern of dwarfing genetics as the F2 seeds and you haven't gained anything. If neither gene is present, then you won't find any dwarf/micro plants in the next generation.
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Back-crossing to the larger-fruited parent variety is a good idea once you've recovered a dwarf/micro. It will increase the odds of having large-fruit genes. If you back-cross before you've recovered the dwarf/micro growth habit, then you will just be diluting the growth form genes and reduce the probability of finding them later.

I would go with recurrent backcrossing as recovering big fruits seems difficult, but as your working with recessive genes, each backcrossing round will take 2 years. And i guess fruit size is lined to many genes like the number of flowers by plant, etc ...