Micro-tomato crosses

[Darren Abbey]

Here's a whole flat of 18 of the (red robin×sungold f1) f3 plants. Boy does it seem like they grow slow. I just have to keep reminding myself that the are micros and are growing along just fine.

When they're blooming before they're 2 inches tall, it sinks in that they're not your normal tomato type.

[kayrobbins]

My HMCC plants are loaded with blooms but no tomatoes yet. They have not dropped any of the blossoms. Out of the 20 plants I kept only 3 have the curled leaf. Most of the plants are about 6 inches tall but I have two that are at least 2 inches taller than the rest.

[Labradors2]

Looking great Kay!!!!

Linda

[ChrisK]

awesome! i sent you a generation earlier from what i have growing, to reselect good lines. hoping for good taste!

[ChrisK]

Are these under lights or GH? What size pots are they in?

Originally Posted by kayrobbins

My HMCC plants are loaded with blooms but no tomatoes yet. They have not dropped any of the blossoms. Out of the 20 plants I kept only 3 have the curled leaf. Most of the plants are about 6 inches tall but I have two that are at least 2 inches taller than the rest.

[kayrobbins]

They are under T-8 lights. I had six of them under LED lights as a trial but they do not look as good even though they do have blooms. I don't have a greenhouse but I do have a structure that I keep thinking could be converted to a small greenhouse.

[KarenO]

100% germination and 100% curled leaf seedlings. at 4 leaf stage so still very little.
KO

[kayrobbins]

I forgot to answer about the pots. They are in 6 inch pots.

[dfollett]

Amazing! I hope they set. Kind of a weird picture, but I thought the one taken in the dark with flash emphasizes just how many flowers are on this baby.

[ChrisK]

Heck, even if only 1/2 of them set it'll be loaded! Looking fantastic!

[dfollett]

Will this multi-flora act on a cross like a typical dwarf at the F1 stage? That is:

1. If it is the female in a cross (MMF x Indeterminate), will the plant from F1 seed be normal sized because of dominance?
2. Will the F2 seeds then be 25% micros or are the odds more (or should I say less) than 1:4?
3. Once they have manifest as micros will that trait then be fixed for future generations?
4. Same questions, but what if the male in the cross is a typical dwarf instead of full sized, but not micro?
5. What is the dominance/recessive relationship between these and a typical 'full size' dwarf?

I've tried several crosses (with pollen from only two plants so far, but 40+ flowers hoping some take). I may try some additional crosses while these are flowering like crazy and I have pollen available. I'm obviously hoping for an easy way to know at the F1 seedling stage if the cross took or not without having to grow everything out to know for sure.

(Is it obvious that I don't know much about tomato genetics?)

By the way, mid-January is when tomatoes start flowering again after the winter solstice without supplemental lighting (at least at this latitude). They stop flowering from about a month before to a month after the December 21 magic day. They're just starting to flower here again now. So, I'll have several different plants I could get pollen from - mostly F1 crosses from last summer I am growing out to have the seed ready for this summer.

[ChrisK]

The F1, regardless of direction of cross, will be a full size plant. Thus, when crossing with dwarfs it is good to use them as the females. If the resulting plants are full size you know the cross took. If they are dwarf you know it is a self.

On the other hand, if you use the full size as the female all resulting plants are full size regardless of whether it is a self or successful cross. You have to grow them to maturity to determine if the cross was successful. As you get more comfortable with crossing your success rate will increase and you will not need to worry about direction of the cross.

I believe the micro trait is controlled by at least two genes in Red Robin (I got micro and dwf as you saw in the picture) but I've never done the segregation and chi square calculation to verify since I'd have to grow a couple hundred to determine. So if two genes, 1:16 will be micro. (1/4 x 1/4) If three genes 1:64 (1/4 x 1/4 x 1/4) (this is what I assumed for micro and multiflora to determine how many F2 to plant to find what I wanted)

Yes, once dwarf/micro they should be fixed in future generations.

If you cross these micros with a dwarf you should get all dwarf and no micros in the F1 (again with the assumption of two genes min. for micro). The F2 should segregate with 25% micro 75% dwarf. The dwarfs in the F2s may show variation because the d alleles in the micro and the dwarf may not be identical, and thus may show some segregation.

Hope that answers the questions (and that I didn't make any mistakes...I'm sure someone will chime in if I did)!

I can draw the Punnett squares if you'd like to see visually (or you can try it!)

Originally Posted by dfollett

Will this multi-flora act on a cross like a typical dwarf at the F1 stage? That is:

1. If it is the female in a cross (MMF x Indeterminate), will the plant from F1 seed be normal sized because of dominance?
2. Will the F2 seeds then be 25% micros or are the odds more (or should I say less) than 1:4?
3. Once they have manifest as micros will that trait then be fixed for future generations?
4. Same questions, but what if the male in the cross is a typical dwarf instead of full sized, but not micro?
5. What is the dominance/recessive relationship between these and a typical 'full size' dwarf?

I've tried several crosses (with pollen from only two plants so far, but 40+ flowers hoping some take). I may try some additional crosses while these are flowering like crazy and I have pollen available. I'm obviously hoping for an easy way to know at the F1 seedling stage if the cross took or not without having to grow everything out to know for sure.

(Is it obvious that I don't know much about tomato genetics?)

By the way, mid-January is when tomatoes start flowering again after the winter solstice without supplemental lighting (at least at this latitude). They stop flowering from about a month before to a month after the December 21 magic day. They're just starting to flower here again now. So, I'll have several different plants I could get pollen from - mostly F1 crosses from last summer I am growing out to have the seed ready for this summer.

[dfollett]

Thanks for the info!

So, to find a micro that is also multi-flora from a cross out of one of these adds another (1/4 x 1/4 - how many times?) to the equation, I assume? And you would need to grow those out fully (at least to where they start flowering) to find, I assume? That's where the haystack comes in and get pretty large.

That makes it easy to decide to not make too many different crosses....

Originally Posted by ChrisK

The F1, regardless of direction of cross, will be a full size plant. Thus, when crossing with dwarfs it is good to use them as the females. If the resulting plants are full size you know the cross took. If they are dwarf you know it is a self.

On the other hand, if you use the full size as the female all resulting plants are full size regardless of whether it is a self or successful cross. You have to grow them to maturity to determine if the cross was successful. As you get more comfortable with crossing your success rate will increase and you will not need to worry about direction of the cross.

I believe the micro trait is controlled by at least two genes in Red Robin (I got micro and dwf as you saw in the picture) but I've never done the segregation and chi square calculation to verify since I'd have to grow a couple hundred to determine. So if two genes, 1:16 will be micro. (1/4 x 1/4) If three genes 1:64 (1/4 x 1/4 x 1/4) (this is what I assumed for micro and multiflora to determine how many F2 to plant to find what I wanted)

Yes, once dwarf/micro they should be fixed in future generations.

If you cross these micros with a dwarf you should get all dwarf and no micros in the F1 (again with the assumption of two genes min. for micro). The F2 should segregate with 25% micro 75% dwarf. The dwarfs in the F2s may show variation because the d alleles in the micro and the dwarf may not be identical, and thus may show some segregation.

Hope that answers the questions (and that I didn't make any mistakes...I'm sure someone will chime in if I did)!

I can draw the Punnett squares if you'd like to see visually (or you can try it!)

[ChrisK]

Each phenotype you are looking for adds another 1/4 (assuming simple dominance/recessive single gene trait and no linkage between the genes). So if you want, PL, dwarf, micro, multiflora only 1:256 will have all those recessive traits if you cross to a full size PL plant in the F2.

[dfollett]

So, if I eliminate the PL from the equation (unless it shows up coincidentally), it becomes a 1:64 search in the grow out of the F2s looking for dwarf, micro, multiflora if I cross this with an normal indeterminate (unless the micro trait is controlled by three genes, in which case it goes back to 1:256) - Correct?

It looks like I'm going to need to buy another shelf and a couple more lights to accommodate all the seedlings..... (and thanks for your patience).

Originally Posted by ChrisK

Each phenotype you are looking for adds another 1/4 (assuming simple dominance/recessive single gene trait and no linkage between the genes). So if you want, PL, dwarf, micro, multiflora only 1:256 will have all those recessive traits if you cross to a full size PL plant in the F2.