Inheritance of ry (reddish yellow, ”bicolor”)

[Pippin]

Yet another theory for the reddish yellows from crosses with Green Sausage. Just recording it here for completeness.

GS has assumably r and gf genes but it could also carry a third recessive gene that impacts the lycopene pathway, such as some of the ripening inhibitors like rin, alc or similar. Something that does not completely block red flesh in the homozygote or heterozygote form. It would not be visible in the GS phenotype as orange tint because y prevents the expression. Now this hidden third gene would become visible again in F2 because I used red as the other parent. Definitely not ry, as I understand it now.

Out of all theories, I like the potassium deficiency the best.

Will hopefully learn more next summer when growing F3s.

[bower]

These are all good possibilities, Pippin. Score for finding the complete lot!
I had a black fruit X Beta orange line, which were also somewhat susceptible to potassium defects - the range of different 'colors' and bicolor looking things was so perplexing one year I just gave up on it and have not grown them again.
But I'm really looking forward to growing a cross with the real bicolor genes, especially since I tried to cross my favorite Oaxaca Jewel PL many times and ended in failure - she rejected all the crosses I made. So I finally used her as pollen donor and, oh well, I guess it will be 2022 before I get to see any results. Looking for a determinate F2 is also going to be a bit of nuisance, I'll need lots of plants to get bicolor as well.
Can't wait to see your F3's... please post some pics if you can!

[Pippin]

I have a similar challenge with my Aftershock F2 screening this following summer, also looking for bicolor determinates from a cross with PL indeterminate.

I was thinking of removing all potato leaf F2 seedlings as soon as I can because I assume Afterschock could have the recessive form of the c (cutleaf) gene, i.e. potato leaf. I just learned that c is part of the classical linkage group in chromosome 6, so close to sp (and B and og) that the link does not break easily. If this trick works, then 50% of the F2s should have the sp gene (instead of normal 25%).

It may seem as an unnecessary risk to loose all good looking, broad leaf forms. C is probably not the only gene that produces broader leafs and the link may not be there. However, if my guess proves to be wrong and there was no link between the leaf form and sp, I should still see the normal 3:1 ration of sp’s in F2 and the broad leafs should segregate back in my determinate F3s if I continue with multiple lines and enough individuals. So I wouldn’t really loose anything for trying this selection strategy. Or at least I have a chance of gaining back what I potentially lost.

Here is a reference https://www.ias.ac.in/describe/article ... /0123-0133.

Chromosome IV group. An F2 repulsion population segregated 117CSp :52Csp :50cSp :0csp, and the corresponding back-cross made after the double recessive was finally obtained gave the ratio 3CSp :90Csp :81cSp :2csp, cross-overs being 2.8+%0.9 percent

[Pippin]

I was hoping to figure out the mystery of my Green Sausage cross this season when screening more of the F2/F3 populations, however, I can only report some observations rather than declare the mystery resolved. As a reminder, I did some pre-screening last fall/winter and I did saw something that reminded me of "bicolor" (ry) - which made me start asking experiences on it.

Anyway, the comment from @Bower on potential potassium defect seems like the best explanation. Such option did not come to my mind originally and I didn't know it could be inherited genetically. It seems that there are several ripening disorders, and most are related to factors that limits the supply of potassium to maturing fruit.

‘Blotchy ripening’ usually refers to the disorder when parts of the fruit surface remain green, yellow, or orange and do not ripen. ‘Yellow shoulder’ is the term used when the discoloration occurs on the “shoulders” of the fruit, surrounding the stem. ‘Gray wall’ is the term used when the outer fruit walls turn brown or gray and collapse, compared to ‘internal whitening’, which refers to when the outer and inner fruit walls become white and corky.

https://ag.umass.edu/vegetable/fact-she ... -disorders

I did observe some uneven ripening on these Green Sausage crosses this season at the beginning of the season during the heat weave. Below some pictures how they looked like.

IMG_5902.JPG

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Later in the season when the weather was more favorable, the tomatoes did actually ripe. For example, the "purple" tomatoes below (extra pinks and reds as color reference), were still were very slowly ripening, sweeter at the bottom where the ripening obviously started, firmer at the top. I am not sure if these really are purple tomatoes (having the gf gene) as the color is closer to "rose" than "purple". I did save seeds from one "rosy" plant because the color was novel to me and the tomatoes remain firm very long time. Not sure if I would recommend using Green Sausage in crosses though: it is an interesting parent obviously but flavor wise it has been little disappointing and it may carry some less desirable genes. My F1 was very sweet and delicious though.

IMG_6247.JPG

[Pippin]

Next to the experiences with the actual ry/bicolor gene. I was also screening the F2 from a cross between Aftershock and a pink cherry. I sowed some 100-120 seeds, then cut out all PLs, dwarfs and indeterminates, and in the end, had seven determinate plants. Out of these seven, three had the ry gene. So, it seems that working with the ry is really easy, just find a bicolor and cross it with your favorite other parent. As discussed earlier, I would recommend using the wild type red (R) in the cross as the other parent, not yellow (y) - as the bicolor does not seem to require both r and ry to be expressed.

I got one yellow bicolor and two green bicolors. The bottom green has green shoulders and top is uniform. Interestingly, the uniform green has more red expressed than the one with green shoulders. Not a scientific proof that there is a dependency, just an observation.

985137F5-54A1-4055-9E76-6AF5AC696650.jpg

Below, you can see the same yellow above at more ripe stage, and interestingly it looks more orange than bicolor or yellow. This makes me think that maybe some of the orange toms out there are actually ry's.

IMG_6311.JPG

[Rockoe10]

Very cool! And i wonder, aren't there two different genes for an orange tomato? Something called "Tangerine", that is what it looks like you have. Just something that popped out to me, that could be the mix up for some "orange" tomatoes

[Pippin]

Interesting thought. There are more than two orange genes in my understanding (at least Beta, Delta and tangerine), and none of them were involved in this cross. One of the parents should have shown some orange, and neither were doing that. In my opinion, this "orange" is a simple mix of yellow and red (which just looks orange together).

[bower]

I've really been wondering about the different alleles of r (yellow), as there are very distinct different types, and I suppose they might also lend some of that different shade in the bicolor? Not sure. I have some yellows as well that ripen a very intense shade almost orange...
I've also been wondering whether the bicolor I used in my cross is also tt tangerine. It does have more of an orange glow than mere yellow, so it might be the case. And I agree with Rockoe that there could be tangerine in that last fruit of yours Pippin. That would be doubly recessive though so it would be harder to find if you were looking for it. Beautiful color either way!

[wykvlvr]

I have been looking for an early bi color (75 days is pushing it here, anything over 80 days is a nope won't beat the snow) and I came across Dagma's Perfection at Tomato Growers Supply. They claim 72 days which might work but would be cutting things close if I wanted ripe tomatoes... BUT they also claim it is a pale pastel yellow with light red stripes... so possibly it is actually that light yellow allele. The few other places I have found it simply say yellow with pale red stripes so who knows.

[bower]

@wykvlvr Northern Lights is a good one that just makes it for our short season. Oaxaca Jewel PL is the earliest one I've found, and seemed to get earlier every year I grew it here.
There is also Big Hill which Joseph Lofthouse released under OSSI as breeding material. It is early and determinate and reportedly tasty.

[wykvlvr]

@Bower that is one I will have to try. Had not heard of Big Hill so will have to look that one up as well as Oaxaca Jewel PL grin I love potato leaf they see to do very well here.

[bower]

I have seeds of OJPL and Northern Lights somewhere in the stash, if Gary doesn't have em - send a pm if you need em.

[Pippin]

@Bower @Rockoe10 I have to admit that I am still troubled by the idea that a tangerine gene could be coming from Aftershock. The probability is at least low in my opinion because otherwise there should be more orange hue in Aftershock. It has very green fruit at least at the beginning of the ripening. The amount of red seems to be increasing over time though. The other parent has no tangerine that is for sure. But I am open to other interpretations too, how boring this would be if anyone didn’t challenge or share a different perspectives?

In theory, I could of course test the theory by crossing my ”orange” with a tangerine to see if the F1 was orange or red. Unfortunately, my orange will not go forward in my project because it has some other unfavorable charasteristics. However, I have been thinking of crossing one of the green bicolors with a tangerine. So maybe I am able to share a pic of tangerine bicolour some years from now. Not sure how to recognise that though assuming the tangerine flower colour may not express at such combo?

@wykvlvr Interesting that you were asking about early bicolours. All my Aftershock F2s were very late. I need to start paying a special attention to earliness on this crossing line.

I grew Marina’s Praise this season (that has orange russian 117 in the pedigree), and would consider growing it again. Maybe worth trying. Not sure how it would rank in terms of earliness but I didn’t have any problems in getting good harvest from it.

[bower]

I have F2 seeds for next season, my cross between OJPL bicolor and a black-brown beefshaped Skipper. There are a load of recessives, I have to select for determinate growth and then find bicolors. If tangerine is really present in OJPL, I would expect to see some different shades of bicolor down the line, with yellow vs orange flesh, and it should be distinctive enough as long as both types occur..
Also have F2 seed of tangerine crosses from Datlo and Amish Yellowish Orange Oxheart, again having to select for determinate and the recessive tangerine, so may take several generations just to get some plants with both traits.
After that, who knows? I might do some crosses with the bicolors for curiosity sake, depending what I think of the tomatoes.
Just sayin, wait enough years and we'll figure everything out.

[wykvlvr]

I do have seeds for Northern Lights that I got from Bunny Hop last year so I can try them in spring. Big Hill was a new one to me so I had to do a bit of research on it. I just made a post on Facebook in the Tomato Breeders group tagging Joseph Lofthouse. Giggle we had just been "talking" about flower size on my micros so I felt "safe" asking about bringing in that flower size (like a daisy in one comment about Big Hill) to my micro dwarfs. Along with the bi color gene of course...

[Rockoe10]

An accidental cross is possible but I tend to I think it has more to do with the genetics of the micro dwarfs. Unlike dwarf tomatoes that have a set look and genetics that make developing more dwarf varieties fairly easy, Micro dwarfs are defined by their lack of height not by any specific genetics. I have noticed 3 very distinct types in the ones I have grown. Flat sprawling big leafed plants that rarely top 4 inches tall. Stout trunks with rugose leaves that resemble tiny dwarf plants. A bit rangier and often taller are the ones that look like small determinate plants but are under 20 inches tall regardless of pot size. I think is is possible when crossing different types you could break the linkages causing the small size and oops full size plants happen. I don't have any proof but the theory does make sense.

Just saw this post in response to my earlier post, sorry for missing this.

Yes, i understand now. Different alleles located at separate locus can have similar affects on the phenotype of each plant, ie. a micro. So when two micro plants with similar phenotypes and distinct genotypes cross, the F1 generation can have their mutated alleles at each locus "fixed", resulting in a traditional sized plant.

[wykvlvr]

It is now winter here so any crosses to a bi color will have to wait until spring but it looks like the plan will be to try Big Hill as the parent to one possible bi color line and probably Northern Lights for a second. My friend has said she will grow out F2 plant for me so that increases my chances of getting a good small tasty bi color.

[Doffer]

An accidental cross is possible but I tend to I think it has more to do with the genetics of the micro dwarfs. Unlike dwarf tomatoes that have a set look and genetics that make developing more dwarf varieties fairly easy, Micro dwarfs are defined by their lack of height not by any specific genetics. I have noticed 3 very distinct types in the ones I have grown. Flat sprawling big leafed plants that rarely top 4 inches tall. Stout trunks with rugose leaves that resemble tiny dwarf plants. A bit rangier and often taller are the ones that look like small determinate plants but are under 20 inches tall regardless of pot size. I think is is possible when crossing different types you could break the linkages causing the small size and oops full size plants happen. I don't have any proof but the theory does make sense.

Just saw this post in response to my earlier post, sorry for missing this.

Yes, i understand now. Different alleles located at separate locus can have similar affects on the phenotype of each plant, ie. a micro. So when two micro plants with similar phenotypes and distinct genotypes cross, the F1 generation can have their mutated alleles at each locus "fixed", resulting in a traditional sized plant.

Is this the case with some of the r (yellow flesh) genes?

[Pippin]

We seem to be merging discussions under different topics now.

My understanding is that the dwarf genes are just different recessive genes. They are not allels of the same gene in the way the different yellow flesh genes (r) are. Allels means versions of the same gene. A cross between different recessive traits (like different types of dwarfs) gives the dominant (or wild type) in F1.

I believe all r variants have a defect of some kind in the phytoene synthase (Psy1), either in the Psy1 enzyme itself or in the reculation system that initiates the encoding of the Psy1 enzyme in right place in the plant at right time. In both cases there is no functional Psy1 enzyme available in the ripening tomato leading to yellow flesh tomatoes. With this logic, the bicolor ry gene (also an allel of the r, right?) could be a defect in the regulation system as the Psy1 enzyme must be available in some parts of the fruit making them reddish yellow.

Typically, the cross between two allels of yellow flesh r tomatoes is yellow in F1. One scenario when the cross could give you red tomato in F1 generation is the one when one parent has a defect in the enzyme (but the encoding activates correctly) and the other parent has a defect in the regulation system (but has a functional Psy1 enzyme). So the allelic r genes in the cross could be able to fix each other.

[Pippin]

Coming back to this old discussion about the inheritance of bicolour (ry).

I crossed a F3 yellow tomato from my Katie line (F2 in the pic left top) with a GWR bicolor tomato from my Aftershock line (left bottom) in the Spring and managed to just today harvest the F2 seeds from the F1 plant (right). Many of the F1 fruits are very ripe, some little less so. It seems that the bicolour expresses already in the F1 generation, as speculated earlier in this discussion. Interesting that the F1 is the reddish of them all. But maybe the pic little lies because the GWR bicolour is more on the underripe side and has clear skin and for this reason may look so much less reddish. In my experience so far, the amount of red in this bicolour line increases when the ripening progresses.

EC083FB4-D481-45CC-8F85-75D7288F8AAA.jpeg

I suppose this also means that in such a cross the bicolour treat can be lost in later generations because the bicolour is here coming only from one parent. Which also means that the bicolour is easier to stabilize from a cross with non-yellow parent (like red or tangerine).

I made the cross just to see how the F1 looks like. I have a sibling cross with red Katie line in case I don’t want to follow this cross further.