Breeding for Pastes

[crmauch]

Originally Posted by maf

That 'belief' is a very plausible possibility. There is also the possibility that different modifier genes exist or that introgressions of B from different species are different alleles with slightly different effect. I don't know enough to say for sure, but I know enough to rule out tangerine.

There are differences between "B" genes see the article I listed earlier http://fic.osu.edu/Orchard_OARDC_20141.pdf, but for a 'home' breeder, I'm not sure that the differential is that significant. From a 'gene/allele' list there are 3 other 'B' gene allelles, two which promote lycopene and the other is a beta carotene promoter (allelle 'm'), but I'm not sure it's out in the world (when you search on that gene and allelle only the other allelles are shown).

PasteBreedingBGenes.jpg

Originally Posted by maf

How tight is the linkage with sp? If not too tight it might just be a case of a slightly larger growout needed to find an indy Beta from that line.

That's something I haven't been able to find out. I know it's possible (as indicated by JF), but how much a PITA it will be.

Originally Posted by maf

In the line crossed to JF you should be able to get back to the original colour of JF if that is orange enough for your needs.

That's true. However though I think JF is a great tomato, it's hybrids were very, very juicy. So paste breeding will be arduous (looking for orange, paste (i.e.dryer), taste), but hey the indeterminate part would be easy!

Originally Posted by maf

Also I believe that the Sungold and Sun Sugar types have the Beta gene, so that might be another source of the Beta gene linked to indeterminate rather than determinate.

They might be beta, I don't know, the genetics seem a little strange to me. I guess it would explain the appearance of 'red' from an orange tomato.

[Fusion_power]

That's something I haven't been able to find out. I know it's possible (as indicated by JF), but how much a PITA it will be.

3 in 1000 are the chances. The distance is about 80 cM.


Also, Sungold is a good example to work from. It is derived from S. Habrochaites so has a similar origin with Jaune Flamme. Sungold can only give the red from an orange tomato type if red is hidden by Beta. It can't be moB/moB or the orange color would be much more intense.

[bower]

Wow... those are really low chances.
Last year I crossed one of my ZS X F1's with a semi-determinate black F2, and expected the odds to be 1/2 sp/sp and 1/2 black. But only one in 4 would have a single Beta allele. I grew 4 plants this year, got 2 black, no Beta, and 0/4 sp/sp - all indeterminates. Now I understand that the sp from ZS is segregating only with the Beta allele... who knew.
Very helpful information, thank you all.

[crmauch]

Originally Posted by Fusion_power

This french document adds several steps to the carotene biopath. I found it very good reading especially since it quoted some of the documents above. See page 32 for details and 33 for a diagram. http://ethesis.inp-toulouse.fr/archi...1/grimplet.pdf

Unfortunately, I don't even come close in being able to read French.

Originally Posted by Fusion_power

Adding up all the available information, Jaune Flamme cannot have yellow, apricot, or tangerine. The only valid explanation is that it has a modified Cyc-B which does not convert all the lycopene into Beta Carotene. This explains the phenotype of the Jaune Flamme X Opalka cross. By extension, it implies a different Cyc-B for 97L97 which is much more efficient at converting to Beta. This explains the phenotype of the 97L97 X Opalka cross. This implies that a modified Cyc-B and Mo-B combined are the difference between 97L97 and Jaune Flamme. http://www.chem.qmul.ac.uk/iubmb/enz...erp/carot.html

There is only one thing that needs to be added. mo-b is recessive and results in 97L97 colored fruit. MO-B is dominant and results in fruit with roughly 50% lycopene and 50% Beta Carotene. Crossing MO-B (dominant form) with a normal red tomato would increase the amount of retained lycopene and decrease Beta Carotene levels but should give roughly the same total amount of carotenoids. http://hortsci.ashspublications.org/...2/387.full.pdf

Well what I said earlier was obviously off in that mo-b (converting the partial beta-carotene to all beta-carotine) is recessive. I see two possibilities (one very unlikely). Is there any documentation what mo-b does in absense of B? I'm guessing nothing?

I agree that the B in JF seems likely to be a less efficient at converting to BC. Would it still give the 90% BC in the presense of mo-B?

Breeding scenarios:
BreedingScenarios.jpg

I don't think the second scenario is true as I got orange tomatoes when crossing with 97L97 with both Opalka AND Heidi. Believing them to both have the recessive mob-B gene is just too unlikely.

See if this statement seems true:
In subsequent F generations of 97L97 if a plant is indeterminate is likely to be heterozygous for B (Bb). If it is homozygous (BB) it likely is to be determinate.

(The only way I see in my current scenario is to select for indeterminate and look for a plant whose subsequent generations throw no reds (or determinates)).

If 97L97 in heterozygous form (Bb) phenotype is orange, how would I, as a home breeder select for mo-B?

I'm now toying with the idea of going back to the breeding 'board', and crossing JF and 97L97. If there's a way to test for the presence of mo-B, then I could combine the non-linked B of JF with the conversion power of mo-B.

[crmauch]

Originally Posted by bower

Wow... those are really low chances.
Last year I crossed one of my ZS X F1's with a semi-determinate black F2, and expected the odds to be 1/2 sp/sp and 1/2 black. But only one in 4 would have a single Beta allele. I grew 4 plants this year, got 2 black, no Beta, and 0/4 sp/sp - all indeterminates. Now I understand that the sp from ZS is segregating only with the Beta allele... who knew.
Very helpful information, thank you all.

bower, I'm a little confused here. Was your ZSXF1 an indeterminate?

[Fusion_power]

I don't know enough to answer those questions CR, but a carefully chosen cross of (97L97 X Opalka) X (Jaune Flammee X Opalka) might have a fighting chance of producing a useful combination. There would be a lot of segregation including some more orange than others and some more indeterminate than others. With judicious selection, I think you might find the intense orange indeterminate paste.

Many of the genes that result in paste tomatoes are located on chromosome 5. This simplifies breeding for paste type.

[bower]

Originally Posted by crmauch

bower, I'm a little confused here. Was your ZSXF1 an indeterminate?

Both of my ZS X indeterminates F1's were very large indeterminates. Orange-red fruit.
The ZS X Black Early F1 was crossed to my Black Nipper F2 - a semi-determinate black cherry selection from the cross Napoli a Fiaschetto (det) X Black Cherry. So two sp alleles coming from the Nipper F2, and one sp from ZS-BE F1, should give a 1/2 chance of sp/sp in the next generation... but chance of a single Beta allele is down to 1/4. No Beta in my 4 plants, and no determinates. I plan to grow a few more of these next year since the fruit were amazing, will let you know what happens when Beta heterozygous shows up.

I also grew out six plants of ZS X Indian Stripe F2 this year. 3 had one Beta allele, judging from the colours. All three indeterminate. Two indeterminate reds. One Beta orange BB, it was semi-determinate.

[crmauch]

Originally Posted by Fusion_power

I don't know enough to answer those questions CR, but a carefully chosen cross of (97L97 X Opalka) X (Jaune Flammee X Opalka) might have a fighting chance of producing a useful combination. There would be a lot of segregation including some more orange than others and some more indeterminate than others. With judicious selection, I think you might find the intense orange indeterminate paste.

That's actually a quite excellent suggestion. I thank you for it. I think at the moment I might pursue 3 directions:
1) A decently large growout of 97L97 X Opalka (f2s).
2) Cross (97L97 X Opalka) X (Jaune Flammee X Opalka) as you suggested.
3) Go back to square 1 and cross 97L97 X Jaune Flamme.

[jmsieglaff]

Crmauch, any updates to color segregation in 2016 with your orange crosses?