Author Topic: Vigor in Tomatoes  (Read 277 times)

William S.

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Vigor in Tomatoes
« on: 2022-05-15, 10:45:37 PM »
F1 hybrid tomatoes can be more vigorous, and I am growing both commercial F1's including Galahad, Cloudy Day, Iron Lady, Purple Zebra, Lizzano, and Sungold as well as a large number of F1 seedlings that arose from MMS in a crossing block and now some new (MMS x BH F1) x Aztek. These all seem to have good vigor.

One of my first observations about Iron Lady F2 is that it has markedly lower vigor than the F1.

I have about 10 or so F1 interspecies hybrids that are Promiscuous x LA2329 Solanum habrochaites. These are growing in two-gallon pots competing with one another and their vigor seems variable from plant to plant.

There seems to be a lot of variation within and between stable tomato varieties for vigor as well. Some seem to have tremendous vigor and others seem to be pretty wispy.

I read recently that Frogsleap farm breeds for vigorous varieties. Hmm I thought. What makes one variety vigorous, and another say pretty wispy or just downright wimpy?

I have the population of my favorite promiscuous project plant from 2021 which I call The One! and it is extremely variable in vigor, and I would not say that any of them are as aggressive as any of the F1 tomatoes I previously mentioned. Does that mean they didn't cross? Or didn't cross with anything with enough heterozygosity for the right traits that they would be aggressively vigorous?

I already get the impression that the (MMS x BH) x Aztek F1 population will be very vigorous. Which is odd because Aztek is such a small plant. Yet I suspect the hybrid has great heterozygosity.

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Andrew Barney

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Re: Vigor in Tomatoes
« Reply #1 on: 2022-05-16, 07:29:39 AM »


I read recently that Frogsleap farm breeds for vigorous varieties. Hmm I thought. What makes one variety vigorous, and another say pretty wispy or just downright wimpy?

I have the population of my favorite promiscuous project plant from 2021 which I call The One! and it is extremely variable in vigor, and I would not say that any of them are as aggressive as any of the F1 tomatoes I previously mentioned. Does that mean they didn't cross? Or didn't cross with anything with enough heterozygosity for the right traits that they would be aggressively vigorous?


I think you probably already know the answer. The most likeliest explanation is genetic diversity more or less for whatever reason causes hybrid vigour. Those with medium genetic diversity probably have medium vigor.

Might be useful to separate some of your tomatoes by vigor and plant them in a sibling line like Joseph does. For your "the one" specifically I would take a guess that the most vigorous might be new hybrids or have the least stable flavor,  while the least vigorous might have the flavor you are looking for (unless the persimmon flavor was the result of F1 hybrid genetics in the first place). Might be interesting to screen for flavor by vigor.

...the conclusion I come to is frogsleap farm is inadvertantly selecting for hybrids and promiscuous tomatoes by heavily selecting for vigour. Hybrids in general have more exerted stigmas too, sometimes purely from the hybrid vigour.
« Last Edit: 2022-05-16, 07:32:51 AM by Andrew Barney »

William S.

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Re: Vigor in Tomatoes
« Reply #2 on: 2022-05-16, 08:09:02 AM »
No hetrozygosity is one very clear source of vigor in tomatoes. It isnt the only one though.

Frogsleap doesn't just produce hybrids but also open pollinated varieties. Thr assertion they made was that they select for vigor in all the varieties they sell. It does seem to be the case that some OP varieties have considerably more vigor than others. So hybridization is not the only causative factor for vigor.

One vigor difference that springs to mind is simply seed quality. Higher quality seed produces good seedlings. Seed quality also changes over time even with the same seed lot. Usually my own seed is more vigorous than bought seed but Mike Jennings sent me some Forest Fire seed that made me think Forest Fire was extremely vigorous and then my own seed didn't perform as well the next year. My conclusion is that Mike grew a higher quality seed lot than I did. Though other factors could apply. For instance if you treat some seed from the same lot with 10% bleach you may notice better germination and greater vigor in the treated lot. So seed quality and seed treatment can lead to vigor. I mention 10% bleach but I would actually use the TGRC bleaching protocol with tomato sèed specifically 10% can be used for virtually all seed.

So:

1. Hybrid vigor
2. Genetic non hybrid op vigor
3. Seed quality vigor
A. Age of seed lot
B. Initial quality of seed lot
4. Seed treatment vigor

I am probably missing some and there are probably tons of sub categories on each of the above.
.
I think part of one way to conduct a really good tomato variety trial would be to first bleach all seed lots. Secondly grow seed for each variety the first year making sure it is all selfed. Thirdly grow each variety a second year again bleaching all seed with the TGRC protocol.





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Andrew Barney

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Re: Vigor in Tomatoes
« Reply #3 on: 2022-05-16, 09:11:05 AM »
I disagree. I didn't say the varieties produced by frogsleap farm are F1 hybrids, but I am saying that their OP varieties have a HIGH amount of hybrid vigour because of partial heterozygosity. Their varieties are known widely for NOT being stable, even Baker Creek has mentioned this when selling some of their varieties. This is not a bad thing, infact quite the opposite. It also partially explains why they have a much higher rate of outcrossing and spontaneous hybrids. It is not the only factor when it comes to outcrossing, but perhaps a significant one.

In the case of vigor related to seed age vs quality... an interesting observation if true. Yeah, seedlings grown from older seed might have less vigour and probably do. But if all the seeds are the same age and grown in the same cell and grown in the same soil and grown in the same conditions and let's say ONE seedling grows better than the rest, then clearly that one has more vigour unrelated to seed quality. Perhaps it has a genetic advantage (such as a better moisture retention in seed). Perhaps it has some heterozygosity (which is another form of a genetic advantage), or possible something else (epigentics?). Basically what I'm saying is it all comes back to genetics if all other conditions are equal. Whether that is because of partial heterozygosity or other genetic factors I don't know for sure, perhaps those two are split 50/50.

But either way I'm not sure it really matters. In my mind you can only select for genetic factors. I can't possibly see how you can select for something like seed quality without actually be selecting for genetics.

This is assuming you are not mixing 3 year old seed with 1 year old seed. Obviously 1 year old seed will have the advantage in most species. But that is not really selection then is it? That's just mixing old seed with new seed and selecting back out mostly the new seed with some that have other genetic advantages (probably heterozygosity).

William S.

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Re: Vigor in Tomatoes
« Reply #4 on: 2022-05-16, 09:47:14 AM »
If that were true than F2's which still have a lot of heterozygosity would generally be more vigorous than say F5's.

However, I have a flat of non-vigorous F2 Iron Ladies that seems to disprove that.

I added in the stuff about seed quality just as another example of a confounding factor to selection for vigor- something which tremendously effects vigor but which can be controlled for. Not saying that we should do genetic selection for seed quality- it is a non-genetic factor.

If heterozygosity were the only factor in vigor, it would not explain, for example, the extreme vigor of some of the very closed flowered currant tomatoes which tend to run rampant in gardens.

In regard to my promiscuous project selection from last year. The mother plant was quite small perhaps exhibiting some form of dwarfing or a similar trait. Some of the seedlings seem quite comparable to some of the dwarfs. However, the mother plant was exserted and had very open flowers from a project designed to promote outcrossing. Its only possible outcrossing partners though were also plants from the project including R18, a couple of Joseph's best flavor selections from 2020 and my own bicolor selections from 2020. They were spaced a little farther apart- say about three feet. It will be very interesting to taste the resulting tomatoes to find out if they give any evidence of outcrossing, but it is just an interesting initial observation that seedling vigor varies from really bad to OK, but none are anything like a Lizzano F1 for example in terms of vigor.

Dwarfing genes are another interesting topic maybe to think about in terms of vigor. Some dwarf seedlings seem much more vigorous than others both within and between varieties.
« Last Edit: 2022-05-16, 09:57:28 AM by William S. »
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Andrew Barney

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Re: Vigor in Tomatoes
« Reply #5 on: 2022-05-16, 02:23:41 PM »
Hmm. Ok. Idk then in regards to your F2 vs an F5. Unless we are comparing old F2 seed vs newer F5 seed. I will assume that is not the case. Must be some other genetic factor then.

I would think if one could use as tightly controlled variables as possible that an F2 would in general be more vigorous than an F5, but that would pretty much be impossible to test.

Regardless,  an interesting discussion.

I still think it might be interesting if you plant your "the one" in a sibling group row organized by most to least vigorous and see if there are any differences by the end of the season, especially in taste and flavor.

Steph S

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Re: Vigor in Tomatoes
« Reply #6 on: 2022-05-16, 03:51:47 PM »
I'm not really sure what all should be included in the definition of "vigor".   Rapid growth?  Sturdiness?  Robust health?  High yield?  What are the defining features?

I have not found excessive vigor as in rapid growth to be always a helpful trait in my growing environment, which has a tendency to push plants toward vegetative vs reproductive growth.  So I have been focusing on fruit to shoot ratio as a way of evaluating my plants.   There are some lines I've back burnered because they were just too big and burly for the amount of fruit in a short season - or simply grew too large for the space and required too much maintenance for that reason.

I do think of vigor as a standard in tomato seedlings, where weak or slow growing individuals stand out - as do the precocious or extra large ones.  The weak tend to be the discards that don't get a pot, but the rest are usually pretty even, or close enough.  It comes down to things like internode length, demand for light, which in excess is not a plus for my goals.

I do also agree that some OP's are exceptionally vigorous and high yielding, it is noticeable for the yield.  Malachite Box for example comes to mind.  PI120256 was also physically vigorous but not early or high yielding - however the 'vigor' combined really well with earliness from other parents, and all of those lines are fast growing and productive plants.  Some plants can be high yielding in one year but a disappointment in a different season.  So it's not that easy to evaluate outstanding vigor/yield - except where it's commented by many different growers in different environments.

Ocimum

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Re: Vigor in Tomatoes
« Reply #7 on: 2022-05-17, 11:17:01 PM »
Have you thought about the possibility for the reduced vigour to be outbreeding depression?

In some crosses, the F1 is more vigourous than the parents, the F2 less than the parents, and with selection you can develop lines which are as vigourous or more than the parental lines.

William S.

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Re: Vigor in Tomatoes
« Reply #8 on: 2022-05-17, 11:30:21 PM »
That could easily be the case in Iron Lady. I have this outstanding question about Iron Lady as to what it segregates like just out of curiosity. I've grown it a couple times now because Carol Deppe recommended it in her book but also suggested diluting it to get rid of the bad flavor. I hadn't bothered to grow the F2 yet. I did manage to get one F1 plant from the last of my original seed packet. So I have the F1 and the F2. I guess I will have to try to remember to collect seed and grow the F3 next year.

Also on another note: here is the variation in the youngest flat of "The one!" It is pretty variable but seems consistent as well. They all have the very dwarf-like character. They range from pretty nice seedlings to crud.

I don't have a handy picture but the youngest dwarf seedlings have just three or four seedlings each and they vary from good to bad amongst the three or four.

« Last Edit: 2022-05-17, 11:51:04 PM by William S. »
Western Montana garden, glacial lake Missoula sediment lacustrian parent material and shallow 7" silty clay loam mollisoil topsoil sometimes with added sand in places. Zone 6A with 100 to 130 frost free days