Stabilizing Dominant Traits

**Lee** · July 16, 2015

Stabilizing dominant traits in a cross with recessives is looking to be a pain!

My Ruby F1 cross of Cuostralee x Summertime Gold is proving that out.

I selected a nice red RL plant in the F2 to save seed from for what I've now called Dwarf Cuostralee.
However, from two of my RL dwarf plants (I was able to cull the PL dwarves earlier this year) I've gotten 2/6 throwing out yellow fruit.

While this is not unexpected, it does not make it any less annoying!

It's much easier to select the PL, yellow, dwarf variety out and expect the same the next year......

Lee

**Lee** · July 16, 2015

Also both of my Brawny F6 plants spit out Brown fruit this year when the F5 was red! I think I just need to grow more plants to ensure I get the
right selection!

Lee

joseph · July 16, 2015

One way to fix dominant traits is to grow out large enough sets of sibling groups, and enough sibling groups so that you can select for sibling groups that do not have the undesired recessive trait(s) in them.

Another way is to just play the odds for enough generations that the recessive trait is almost eliminated... Is 99% elimination good enough???

KarenO · July 17, 2015

Just wondering What was the reason for crossing with a yellow dwarf if you weren't hoping for any yellow segregation? What colour were summertime gold's and coustralee's "parents"?
I would think a red tomato should be pretty stable at f6. You are sure there wasn't a cross?

KarenO

Fusion_power · July 17, 2015

This is relatively easy to do Lee, but takes more time. Use single plant seed saving. Pick one fruit from each desirable red fruited plant and save the seed separately. Next year, grow at least 4 plants from each seed group. Select the group that produces only red fruit.

bower · July 17, 2015

I've been looking for a 'tell' for fruit colour in flower colour this year. So far my predictions for black fruit have been correct, but the flower differences in red X yellow F2's were too subtle to call.

I have three plants of a red X yellow that are ripening now - two of them are like the F1: they turn yellow first, then orange, finally red. Since I was looking for yellow, it makes for a bit of a letdown! A third one is yellow now, but that means, wait a while more

......I'm thinking that in this case, the two 'yellow first then red' are heterozygous like the F1. If so, it's a pretty good 'tell' in itself, for next generation prospects.

Also having some excitement over the prospect of pink vs red...

Several fruit with that possibility have blushed a gorgeous pink... only to turn red.

It seems llike the colours this year are designed to raise false hopes and then dash em.

**Lee** · July 17, 2015

Quote:

Originally Posted by KarenO

Just wondering What was the reason for crossing with a yellow dwarf if you weren't hoping for any yellow segregation? What colour were summertime gold's and coustralee's "parents"?
I would think a red tomato should be pretty stable at f6. You are sure there wasn't a cross?

KarenO

Cuostralee is a large red heirloom... best thing on sliced bread.
Summertime Gold is my favorite tasting of all the dwarves. Well Rosella Purple is pretty good too, but this is what I was growing.

So Cuostralee X Summertime Gold -> Ruby F1 with the goal of a large red awesome tasting dwarf.... ie. Dwarf Cuostralee.

Found one pretty close last year in the F2, and grew that this year.

A couple of those are producing yellow fruit, so I only have four red fruited plants to select from. Hopefully one of these will be good enough to continue with the name Dwarf Cuostralee.

I do have one that I'm hoping meets the flavor profile that I'm looking for. It is doing quite well despite other plants around it dying due to Septoria....

crmauch · July 17, 2015

Another thing you could do would be to backcross Cuostralee to your dwarf. Then you'd have to select for dwarf in the f2 again, but the tomato would generally be 3/4 Cuostralee...

This said from someone who has not had a sucessful cross w/ a dwarf as a female parent...

Trying to cross f2 of Dwf StoneXSan Marzano with pollen from San Marzano. No luck yet and running out of time...

July 16, 2015	#1
Lee Tomatopalooza™ Moderator Join Date: Jan 2006 Location: NC-Zone 7 Posts: 2,188	Stabilizing Dominant Traits Stabilizing dominant traits in a cross with recessives is looking to be a pain! My Ruby F1 cross of Cuostralee x Summertime Gold is proving that out. I selected a nice red RL plant in the F2 to save seed from for what I've now called Dwarf Cuostralee. However, from two of my RL dwarf plants (I was able to cull the PL dwarves earlier this year) I've gotten 2/6 throwing out yellow fruit. While this is not unexpected, it does not make it any less annoying! It's much easier to select the PL, yellow, dwarf variety out and expect the same the next year...... Lee __________________ Intelligence is knowing a tomato is a fruit. Wisdom is knowing not to put one in a fruit salad. Cuostralee - The best thing on sliced bread.

July 16, 2015	#2
Lee Tomatopalooza™ Moderator Join Date: Jan 2006 Location: NC-Zone 7 Posts: 2,188	Also both of my Brawny F6 plants spit out Brown fruit this year when the F5 was red! I think I just need to grow more plants to ensure I get the right selection! Lee __________________ Intelligence is knowing a tomato is a fruit. Wisdom is knowing not to put one in a fruit salad. Cuostralee - The best thing on sliced bread.

July 17, 2015	#6
bower Tomatovillian™ Join Date: Feb 2012 Location: Newfoundland, Canada Posts: 6,794	I've been looking for a 'tell' for fruit colour in flower colour this year. So far my predictions for black fruit have been correct, but the flower differences in red X yellow F2's were too subtle to call. I have three plants of a red X yellow that are ripening now - two of them are like the F1: they turn yellow first, then orange, finally red. Since I was looking for yellow, it makes for a bit of a letdown! A third one is yellow now, but that means, wait a while more......I'm thinking that in this case, the two 'yellow first then red' are heterozygous like the F1. If so, it's a pretty good 'tell' in itself, for next generation prospects. Also having some excitement over the prospect of pink vs red... Several fruit with that possibility have blushed a gorgeous pink... only to turn red. It seems llike the colours this year are designed to raise false hopes and then dash em.

July 16, 2015	#3
joseph Tomatovillian™ Join Date: May 2013 Location: Cache Valley, N/E of The Great Salt Lake Posts: 1,244	One way to fix dominant traits is to grow out large enough sets of sibling groups, and enough sibling groups so that you can select for sibling groups that do not have the undesired recessive trait(s) in them. Another way is to just play the odds for enough generations that the recessive trait is almost eliminated... Is 99% elimination good enough???

July 17, 2015	#4
KarenO Tomatovillian™ Join Date: Oct 2012 Location: Vancouver Island Posts: 5,926	Just wondering What was the reason for crossing with a yellow dwarf if you weren't hoping for any yellow segregation? What colour were summertime gold's and coustralee's "parents"? I would think a red tomato should be pretty stable at f6. You are sure there wasn't a cross? KarenO

July 17, 2015	#5
Fusion_power Tomatovillian™ Join Date: Feb 2006 Location: Alabama Posts: 2,250	This is relatively easy to do Lee, but takes more time. Use single plant seed saving. Pick one fruit from each desirable red fruited plant and save the seed separately. Next year, grow at least 4 plants from each seed group. Select the group that produces only red fruit.

July 17, 2015	#8
crmauch Tomatovillian™ Join Date: May 2013 Location: Honey Brook, PA Zone 6b Posts: 399	Another thing you could do would be to backcross Cuostralee to your dwarf. Then you'd have to select for dwarf in the f2 again, but the tomato would generally be 3/4 Cuostralee... This said from someone who has not had a sucessful cross w/ a dwarf as a female parent... Trying to cross f2 of Dwf StoneXSan Marzano with pollen from San Marzano. No luck yet and running out of time...