F2 varieties

[lindalana]

Someone gave me seeds from last year F1 tomatoberry and wants me to grow it for this year swap. I remember growing Sungold F2 years back and it was ok but not the same. Shall I assume it is the same for most hybrids particularly cherry?
Not running any experiments just want to grow what will be decent tomato and not a spitter.

[bower]

Hi Lindalana!
Those seeds from the F1 will not be uniform. The amount of variation depends on the two parents and how different they are from each other. But with a commercial F1 there's no way to know what those parents are like exactly.
I haven't grown tomatoberry F1, but I just looked at a picture.
Size: One parent is a cherry, because cherry size is dominant, so the F1 is a cherry. But one parent may be a larger fruit, even a heart.
Color: Red is dominant, so you may have a different color parent and still have a red F1. They describe it as especially dark red, and one way this can happen is if one parent is black so the F1 is (gf/-). So you may have some fruit not as red as the F1, and one in 4 could be black or brown.
Shape: The heart shape is tricky for a cherry or small fruit... IDK if the F1 shape is very uniform? In my experience, F1 crosses between a cherry and a heart had variable shapes, some heart and some not. But if both parents had the same shape genes, it would be the same in all your F2.
If you want to see the variation in the F2 and choose the best qualities for next generation seed, six plants is about the bare minimum, more would be better.

[pepperhead212]

Another thing that can happen with F2 seeds is becoming sterile. A friend of mine had a volunteer plant that grew in his front flowerbed one time, and the plant grew over 4' tall, and loaded with flowers, but never set a single fruit! No idea what it was from - must have been a gift from a bird or something, because his tomatoes were nowhere close to it.

[Shule]

I've grown lots of F2 tomatoes, and I don't think I've ever found a spitter among them. They have a better track record than the F1s, actually.

[Shule]

That's not to say I've never had an F2 with any undesireable traits.

[maf]

It has been a decade at least since I grew Tomatoberry F1. Mine was Tomatoberry Garden F1 which I believe was the version aimed more towards the home gardener, while other version(s) marketed at the time were aimed at commercial greenhouses, likely with longer shelf life and other commercial adaptations. Never grew out F2.

Judging by the uniform size and shape I would expect both parents to be small and possibly have similar shape to the F1. @bower makes a good point about having possible dark tomato parent as I have seen this myself when growing out the F2 of a different supermarket F1. If it is a commercial, rather than home garden, version of Tomatoberry you may also encounter some F2 plants that do not ripen tomatoes due to rin or similar delayed ripening genes.

Some F1 tomatoes have parents who are very similar in appearance, just with different disease resistance packages, and/or to incorporate heterozygous delayed ripening effects. Others could have completely different appearance. It is really a shot in the dark and only known when you grow out several plants for assessment.

Also, sterile plants were mentioned above - sometimes commercial F1's are made with male sterile mother plants (to avoid having to emasculate them), which would be the reason if you get any sterile plants in the F2.

[bower]

I didn't know that a workable male-sterile system had been developed in tomatoes for F1 seed production. Considering how much is saved in effort, it's not surprising there are new systems being developed all the time.
Three kinds of "positional" sterility, including "exserted stigma" discussed here as being used for F1 seed:
https://link.springer.com/article/10.10 ... 000-0015-4
Genes for cytoplasmic male sterility (CMS) as found in a number of other crops, don't exist naturally in tomato. But with new tools for gene modification, it won't be long til they have found ways to do that too. They have identified the target here, to be modified. 2022.
https://academic.oup.com/plphys/article ... ogin=false

[maf]

I didn't know that a workable male-sterile system had been developed in tomatoes for F1 seed production. Considering how much is saved in effort, it's not surprising there are new systems being developed all the time.
Three kinds of "positional" sterility, including "exserted stigma" discussed here as being used for F1 seed:
https://link.springer.com/article/10.10 ... 000-0015-4

It could well be "functional male sterility" genes like positional sterile-2 (ps-2) that I was thinking of rather than actual male sterility, but I thought there were some types of male sterility in (not widespread) use for some hybrid seed production. It is not a trait I would look for in my own growing and breeding so have not dived too deeply. There are around fifty male sterile (ms-) genes in the TGRC database and articles discussing their usefullness for hybrid seed production were written as far back as 1950.

Anyway, the sterility discussion may be at a bit of a tangent as no evidence that progeny of Tomatoberry F1 is affected by this phenomenon.

Also I meant to mention in my previous post that Tomatoberry is from Tokita Seeds who also bred Sungold.

[bower]

Tokita Seeds do good work!
@maf I have no experience either with growing out commercial F1s or crossing with them, but to the best of my knowledge until recent times at least, they were not successful in designing a male sterile system for tomatoes, and had to do all the F1 crossing by hand.
From what I read over my coffee this morning, there are naturally occurring genes for sterility in tomato which are only in the nuclear DNA. This means it would be passed on, and could end up with the F1 having some difficulties to produce normal fruit with seeds. So these nuclear genes are less useful for F1 production. The natural sterility gene or mutation occurs at a rate something like one in 5,000? So this might explain @pepperhead212 the plant that turned up in your friend's garden. And probably (or maybe) not the result of a stray seed from an F1.
The upshot, for Lindalana's purposes - I doubt that sterile fruitless plants are likely to be a problem in the F2.

[maf]

I've grown out the F2 seed of commercial F1 cherry tomatoes a couple of times that I can recall.

Piccolo - tried this over 15 years ago. Some plants were tasty and similar to the F1 but maybe not quite as good. It also produced some plants with pale fruits that stayed hard and never ripened properly, likely delayed ripening genes rin/rin or similar. I believe Piccolo is a tightly controlled variety only grown with select commercial partners, and can never remember a time when the F1 seeds were available for home gardeners to purchase. If it was available i would buy it for sure, as after all these years it is still the king of supermarket on-the-vine cherries in the UK, great flavour, not just sweetness. OP versions are sold by various companies from time to time and have even made their way to north america via trades etc, but I don't think any have truly matched the original. (Very similar to the situation with OP Sungold types.)

Sugardrop - (the UK supermarket F1 hybrid, not the USA OP with the same or similar name) This was interesting, got all sorts in the F2! The original was an intense red, slightly plum shaped cherry. The F2 were all of a similar shape, but as well as red there were chocolate and striped fruits, can't remember if any had clear skin. Some plants were of determinate and semi-determinate habit, and all seemed to have a height reduction gene that was not dwarf, likely to be brachytic (br). I even grew a few lines out to F4 or so but fruit size seemed to be reducing and none of them matched the quality of the original so it has been shelved for now.

Too much information for this thread, I know, but felt like sharing....

[Doffer]

Maf,

I tasted a Nebula F2 and never god such a good tasting cherry. The brix was 14.
I think its more sweet as Piccolo.

[Doffer]

@bower one of the parrent of Plum Regal F1 have male sterility (ms-10 gene) linked to green stem seedlings.

[bower]

@bower one of the parrent of Plum Regal F1 have male sterility (ms-10 gene) linked to green stem seedlings.

Thank you... very good to know that.
Do you have a reference I can read as well?
I am planning to grow Plum Regal this season and thoughts of crossing with it.
I will have to look up the ms-10 gene and see if that's going to be a problem.
Or, best plan off the bat would be don't use Plum Regal as the mother plant.
Of course, dehybridizing might lead to trouble.
Anyway, thank you so much for saving me trouble that might arise if I didn't know!

[maf]

I was looking through my seed stash today and came across an unopened pack of the hybrid Geo 12 F1 dating from 2016. Interestingly, scrawled on the front in my handwriting is the note "ps2 linked to fulgens". So I looked up the genes and yep, ps2 and ful are on the same chromosome/arm indicating likely linkage. And Geo 12 pops up in the literature on ps2 as one of the hybrids developed that incorporate ps2.

No idea where I got this nugget of information from, but glad i had the foresight to write it on the packet! I have no real use for ps2 but I am now committed to growing the F1 this year and then the F2 later to look for the bright yellow/green fulgens seedlings as a fun but pointless project!

[bower]

fulgens!!! never heard of it. great to know @maf !
Sounds like Plum Regal is the same.

[maf]

Gotta love those marker genes. Likely to be anthocyanin absent (aa), anthocyanin reduced (are) or without anthocyanin (aw) that is linked to ms-10 giving green stems in Plum Regal parent seedlings?

[Doffer]

Yes NC 30P the mother of plum regal have the linked genes:
ms-10 male sterility
aa for green stem

https://mountainhort.ces.ncsu.edu/fresh ... seedlines/

@bower Its very easy to select for the ms-10 genes because of the aa green stem linkaged.

[bower]

Aha - so in fact it is easy to use ms-10 for hybrid F1 tomato production. So it is probably more common already than I thought.

[lindalana]

I am floored with depth of your knowledge , thank you so much for answering!
Am thinking of or the purpose of growing it for the swap to give other people I will need to label it as experimental seeds, "grow at your own risk and bring my seeds back if you like your results"
Thank you again, it gave me better understanding what my expectations might be.