tangerine tangent 2023

[bower]

I have ended up with 18 F2s searching for determinate and tt tangerine this season.

Two years ago I made a cross between a hearty-shaped Rodney F5 and the Amish Yellowish Orange Oxheart which I got from Debbie (thank you @OhioGardener !) As it happened, I was making this cross just at the time of my DIL's father's passing, so I named it Neville to remember him. The goal is to develop an early, well adapted determinate tangerine heart.

The F1 Neville's were a bit different from one another and I kept two of them: one had medium-large smooth mostly heart shaped fruit (Nev 1) and the other (Nev 2) had fairly small, pretty, ribbed heart shaped fruit. I saved seed from both of them as I couldn't decide which I liked best.

And meanwhile I also resurrected an old cross I hadn't grown out, between the Black Nipper (determinate black cherry) F2 and the tangerine cherry Datlo (thank you @MrBig46 !). I grew that F1 last year as well. And now I have six F2 seedlings of each, with a very slight chance of finding both determinate and tt tangerine together.

I know flower color is a very good tell for tangerine, but I recently learned that cotyledons can be used as a tell, if they yellow more quickly than the others, while gf cotyledons stay dark green. The question of foliage color also came up in conversation, and maybe that is another tell? Anyway I noticed that some cots were yellowing while others stayed green, so I marked those for starters.

[bower]

My seedlings were off to a spotty start this year, not sure whether to blame the weather or the potting mix or both. It's a cold spring well below average so it could be the kind of year tomatoes aren't feasible outside the greenhouse. As soon as buds appeared on the seedlings they were potted up into half gallon pots.
The half gallon size worked for me before, to allow the plants just enough room to grow and show their determinate growth habit before getting a full space. So I have the 18 F2's and also 8 F3's of the Bicolor Rumpus from last year - I think 8 plants is enough that a determinate will show up if the genes are there.
They're just getting to the exciting part, where you can tell they are determinate or not, and already I've found, I believe, one determinate each for Nev1 and Nev2. And much to my surprise, they are also both marked with the 'yellow cotyledon'. If they really turn out to be tangerine as well, that would be a crazy score.

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Nev2-ycot2-DET-may22-061.JPG

Nev1-ycot1-DET-may22-067.JPG

[PlainJane]

Looking forward to seeing what happens!

[Frosti]

Interesting observation about the yellowing cotyledons.
I'm pretty sure that anthocyanin concentration can be seen on the (purple) cotyledons as well.
example: 6-22 F2 is a cross with Ananas Bleu.

EBDE2521-E9D5-42FF-AC78-88E8584B1624.jpeg

By the way, I also have a tangerine cross, but I only have 2 plants, both of which still have green cotyledons a few days prior to transplanting. If your theory holds true, then those shouldn't have a tangerine color right?

D57825F2-B479-4C5E-9075-5778752754CD.jpeg

[bower]

@Frosti I hope I got this right, it was actually @Pippin who made the observation, in a conversation on the OSSI forum. There was a paper that he linked as well, which used cots or leaves to identify gf plants, iirc the leaves were placed in the dark for several days, and the gf/gf leaves stayed green while the others yellowed. Really fascinated to see the antho turning up in cots as well!
This effect I've never noticed before, probably because of working with mainly gf/gf lines and Beta, and just assuming all cots were green on the basis of nutritional status.

My plants were a bit more mature than yours, at the emergence of 7th true leaf before I noticed that some cots were yellowing on the t/? plants while others were dark green and most a medium green. There is gf/? in the F2 t/? lines as well. So besides the early yellowing ones, I also marked a couple that were darker green. These may turn out to be gf/gf. All of my other gf/gf known lines retained dark green cots up to transplant, and the known ry/ry plants retained a medium green cot at that stage, similar to their foliage color.
I also noted that the expected ratio of tt and gfgf vs t/- and gf/- was about the same as the cot color ratio.
So if your plants cots don't show yellowing, they might still likely carry the t/- allele for next generation.

Here are a couple of pics, how the cotyledons were looking, and how the canopy colors look at the same time. The tangerine lines actually have mostly a very dark green foliage, that is darker than the gf/gf Rodney plants, at this stage. But duly noted that the Nev and BND F2s had spent the last shift in the window position under lights, and had a lot of antho showing due to the cold, which I believe tends to darken the look of the foliage as well. There have been some shifts in canopy color since they moved to the greenhouse a few weeks ago.

cotyledons-tt-vs-gf-733.JPG

canopyvcot-tt-vs-gf-737.JPG

canopy-gf-vs-tt-715.JPG

[Frosti]

Interesting stuff, @Bower . Gotta look up that paper . I didn't say anything before, but now that you said it ... I also noticed that this line has noticeably darker foliage than other lines. I thought it was something variety specific, though.

[bower]

I should go back and look for the link to that paper.
I did some more sorting this afternoon and examining buds, although it's a no-grow day with temperature less than 60F. It's really noticeable now that some plants have very dark foliage while others in the same F2 group do not. It's not clear to me at this point whether foliage color is segregating separately, because the canopy color doesn't match the cotyledon sign.
The earliest two bicolor Rumpus are opening flowers, they are both indeterminate though, one PL one RL. Skipper Pink is close behind.
I believe I have identified a determinate in the Rumpus F3! Others are still unfolding. There is another PL that looks like it could be but time will tell.

biclr-rumpus-indet-flropen-may22-071.JPG

[jmsieglaff]

I love reading your crossing posts, always so interesting and I learn something every time!

[bower]

Well I went looking for the link to the paper and it doesn't seem to be there, but the thread with the discussion is here:
https://opensourceplantbreeding.org/for ... 794.0.html
But it seems this is only applied to gf, not to tt tangerine, so I remembered wrong. Perhaps those seedlings with the yellow cots are simply the only ones that have no gf allele?
Time will tell.
It's just very cool to find research on these kind of tells, and who knows. Maybe they yellow cots are tt.
Your antho cots as well @Frosti .
Meanwhile I will take a further look at the canopy colors as well, because the differences are striking, at least in the Neville F2 lines.
Hopefully some more 'normal' weather here in the coming week, and start to get some flower colors as well.

[OhioGardener]

Two years ago I made a cross between a hearty-shaped Rodney F5 and the Amish Yellowish Orange Oxheart which I got from Debbie (thank you @OhioGardener !) As it happened, I was making this cross just at the time of my DIL's father's passing, so I named it Neville to remember him. The goal is to develop an early, well adapted determinate tangerine heart.

Exciting! I hope it works out. I need to try again, but I got frustrated trying to cross Amish Yellow pollen with my Premus which seemed to either self-pollinate before I could remove the anther cone or not pollinate at all as a result of me removing the anther cone too soon. I'd love to see a short, determinate tangerine tomato though.

[Frosti]

Well I went looking for the link to the paper and it doesn't seem to be there, but the thread with the discussion is here:
https://opensourceplantbreeding.org/for ... 794.0.html
But it seems this is only applied to gf, not to tt tangerine, so I remembered wrong. Perhaps those seedlings with the yellow cots are simply the only ones that have no gf allele?
Time will tell.
It's just very cool to find research on these kind of tells, and who knows. Maybe they yellow cots are tt.
Your antho cots as well @Frosti .
Meanwhile I will take a further look at the canopy colors as well, because the differences are striking, at least in the Neville F2 lines.
Hopefully some more 'normal' weather here in the coming week, and start to get some flower colors as well.

Thanks for the link! Super interesting discussion. I don't want to hijack your thread but I have to ask about one point in that thread. User "Roland" (maybe he's here on TJ as well?) claimed that dwarfs can be recognized early on by their lack of closing of the cotyledons at night. The source he later provided seems to be the wrong one, at first glance. Can you confirm this, or have you heard about this before? Gotta take a closer look at my last unthinned seedlings. That would be a huge deal.

[bower]

@Frosti I haven't done any work with dwarves myself, so cannot confirm that. Let us know what you find!

@OhioGardener Some plants seem to firmly resist being the mother parent in a cross. Always worth a repeat try though. The lines I'm working with are generally medium sized determinates which may require a bit of late season support (but no pruning), at least in the greenhouse. So the tangerine I'm looking for may be a step towards your goal.. At least avoid the tedious process of selecting determinates vs indeterminates. I'll be happy to share it with you for further crossing with Premus.

[bower]

Still waiting for flowers to open on the F2s, but I have now potted up two determinates each from Nev1 and Nev2. At least a few plants are close to open flower stage so I should have some pics by next weekend, I hope!
I took a pic of the canopy colors this evening. Three Nevs side by side, all similar in vigor and growth stage. None of the three were marked for dark or light cotyledon, so I think it's fair to say the leaf color is independent of that sign. I also have two plants marked for dark green gf type cotyledon, which one has light green and the other dark green leaf.
The darkest leaf is least common, only three plants of 12. The majority are medium green, but one or two seem to be even a lighter green, like the one on the left in the picture. The BND cherry has one dark leaf plant, and the rest look light or medium green.

NevF2-3canopygreens-146.JPG

[nicotomato]

Hi, i'm Nicolas on the OSSI board

Maybe Bower was refering to this post about tangerine young plant foliage :
https://opensourceplantbreeding.org/for ... l#msg12795


I think Roland is here (hi @Doffer !), and i'd love to have some ref to this dwarf seedling selection criteria too

[bower]

Thanks so much Nicolas! I knew I read something about tangerine as well as gf!
Now I will really take a closer look at the foliage colors, and which ones I can hope to open flowers soon. Some are already at the stage where you would emasculate to make a cross, so shouldn't be more than three days I reckon, that is 'tomato degree days' because sadly below 60F the days don't count.

[bower]

Some interesting reading on this subject - apparently there are two different alleles of tangerine. The allele found in microtom is the one that affects carotenoid production in all parts of the plant including leaves and roots. So this is the one that could be identified by the young leaves. The other allele only affects fruit and flower carotenoids.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC152916/
"In wild-type flowers, the yellow xanthophylls neoxanthin, violaxanthin, and lutein make up 95% of total carotenoids. In contrast, the fraction of xanthophylls is ∼50% of total carotenoids in flowers of tangerine-3183 and <10% in tangerine-mic. In both mutants, the flowers accumulate large quantities of prolycopene and its precursors."
"The tangerine mutation also affects carotenoid biosynthesis in chloroplasts, as is evident by the yellow color that appears in the newly developed leaves (Figure 2). Leaves of etiolated seedlings of tangerine-mic, but not tangerine-3183 or the wild type, accumulate prolycopene and its precursors and do not contain any xanthophylls (Table 2). In green leaves of light-grown seedlings of tangerine-mic, the proportion of β-xanthophylls increases at the expense of lutein. "

The microtom allele also causes some serious problems for the plants by almost completely blocking the carotenoid pathway. Drought sensitivity, reduced mycorhizzae, etc.
https://www.biorxiv.org/content/10.1101 ... 1.abstract

More about carotenoids and an updated diagram which explains how the synthesis pathway relates to plant hormones - ABA being a late product in the path, in this review:
https://www.sciencedirect.com/science/a ... 5214000070

[Pippin]

@nicotomato I may be to blame about the confusing dwarf seedling selection criteria going around. I commented something on these lines in OSSI forum earlier, based on a paper that I had read. The paper claimed about non-dwarf seedlings going to sleep at night (i.e. rising the leaves up) and dwards not. At the time of commenting this in the OSSI forum, I thought the authors meant cotyledons but after observing some seedlings of my own later, I think they must have meant the first true leaves.

I cannot remember the original source anymore, it might have been a study that investigated the use of heterozygote dwarf genetics in commercial tomato production. The Dd hybrid is supposed to be 10% shorter than the wild type, so the d still expresses a little in dwarf/non-dwarf hybrids. I think the researchers found some commersial potential from such hybrids.

Edit: here seems to be my posting, no references there, just speculation https://opensourceplantbreeding.org/fo ... ml#msg9994

[bower]

Flowers have been slowly opening, with days on the cool side. This has actually been kind of helpful, because it allowed me to observe the very early stages of the anther cone, as petals half opened and didn't get the heat to push open right away.
In the plants marked for yellow cotyledon, I have so far two R-type flowers... and one tangerine! And the tangerine is one of the determinates. This is great news for the project, even though the yellow cot didn't turn out to be a good tell for tangerine.

What is really noticeable about the tangerine flower, is that the anther cone is darkly colored orange at first opening, even while the petals are still very pale, almost white.
When fully open the petals are still a shade paler than wild type, due to the lower accumulation of xanthophylls.

flower-opening-tt-216.JPG

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[bower]

Some pics of the wild type, red fruited R type flowers for comparison.
Notice that the early anther cone is pale and greenish and too early to call whether red R or gf or r type.
So the R type flower is best to be judged when petals are fully yellow and fully opened, as only then the anther cone has its mature color.
But you can rule out tangerine as soon as you see the pale anther cone.

flower-Rtype-stages-257.JPG

flower-R-cluster-nev2D1-478.JPG

[bower]

Another red type and its very pale early anther cone:

flower-opening-R-325.JPG

flower-R-dkg-leaf-464.JPG