Micro dwarf x Indeterminate cross ideas.

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KaguyaCloud
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Re: Micro dwarf x Indeterminate cross ideas.

#261

Post: # 141718Unread post KaguyaCloud
Sat Dec 28, 2024 11:26 pm

Side Project B: Isolating micro traits via growing out F2 seed.

Hypothesis:
The dwarf gene(d) causes the cotyledons in micro dwarfs to not close during the night cycle.

The gene sp in micro dwarfs might be very different from the typical sp in determinate tomatoes. I went through Pippin breeding projects that bower mentioned and it seems that there's quite a lot of variability in determinate flowering patterns.

The small root trait prevalent in Micro-Tina, Jochalos, and Orange Hat might be a sign of a micro trait. Short roots occurred in 4 out of 20 germinated seedlings, indicating that it is a recessive trait. This may not be entirely necessary, but appears in the smallest micro dwarfs. Vilma and Joro F3-1, for example, have not expressed the small root trait and have a slightly larger, more open growth habit.

Process:
Plan 1:
I could be extremely conservative in individual preservation by seeing the possibility of isolating just sp and d alone. Perhaps keeping track of root length could be part of this as well. If the micro version of sp is different, I should be able to obtain the micro-like growth habit(early flower termination, axillary shoots skipping the vegetative cycle) in only 1 out of 16 seeds germinated. It's possible that this trait may be recessive to other determinate sp tomatoes, as it seems that most people are having difficulties in isolating this trait or have not notice this pattern due to crossing with larger determinates.

Plan 2:
Germinating 16 seedlings at a time in 4 separate batches. Cull all seedlings without the small root trait. Plant the theoretical 4 seedlings in a single 4 inch pot. Of the 4, 1 statistically should have the dwarf trait. Begin germinating the second batch of 16 seeds and repeat until there are 4 pots. Statistically, I should be able to have 1 individual plant with the dwarf gene, small roots, and the sp gene. If there is another gene that controls early flower termination in micros, it is statistically unlikely

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Re: Micro dwarf x Indeterminate cross ideas.

#262

Post: # 141723Unread post bower
Sun Dec 29, 2024 8:29 am

I like the Plan 2 best, if only because larger numbers will help to confirm your ratios and selection process, also giving you more experience with real vs theoretical numbers.
Chris Mauchlin at Tville did a nice piece of work that combined genetic frequency with probability to give actual number of plants you need to grow for percent certainty of finding your recessive trait(s). IDK, I've probably mentioned that before.
Okay I went looking and found that old thread at TV:
http://www.tomatoville.com/showthread.php?t=38505
In the first example given, your chance of finding a one in four recessive with four plants is 68%. I usually bump the number to 6 plants for an 80% chance, and that is enough to find it, more times than not. It doesn't seem like a huge gain in probability, but it is so disappointing to go all season with 4 plants and not find your carry forward.
Obviously you don't have the same seasonal constraints, so it may not really matter, especially since your plan is to start additional waves of seedlings for selection.
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Re: Micro dwarf x Indeterminate cross ideas.

#263

Post: # 142092Unread post KaguyaCloud
Fri Jan 03, 2025 8:26 pm

Update 1/3/25


Out of the 19 fruits from Joro F3-1, I obtained 3 viable seeds from 1 single fruit.
Out of the 14 fruits from Joro F3-2, I obtained 1 viable seed from 1 single fruit.
The pattern of having completely seedless fruits has surprised me to no end, on top of the fact that the size of the fruits are not an indication of pollination.

I have decided I will attempt a backcross on both Joro F3-1 and F3-2 on Rosella. After giving the tomatoes more time on the vine, it seems that Joro F3-1 has much better flavor, not to mention a higher potential yield despite being grown in the same size pot. However, the flavor is still diluted compared to the Pale F2 parent it came from. If isolating the 3 traits still ends up with inferior flavor, I will try my hand in packing even more genes from Rosella by using F3-1 as a more stable flavor reference.

I wonder how small the tomato plant might be if I were to just select for Dwarf and the early termination gene.

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Re: Micro dwarf x Indeterminate cross ideas.

#264

Post: # 142412Unread post KaguyaCloud
Tue Jan 07, 2025 9:02 pm

Quick Update 1/7/25

I accidentally broke off a half ripe fruit(reached past breaker) off of Joro F3-2. I obtained 30 seeds from one fruit. I suppose don't need to worry too much about saving a diverse population seeds anymore. This would indicate though, that the early flowers transferred less pollen than the later flowers. Flowers that were produced later in the flowering cycle in both F3s exhibited high amounts of pollen production and will likely produce a lot of seed as a result.

Is this a normal phenotype for cherry tomatoes? Rosella Cherry and the F1 exhibited similar exerted stigmas in the early flowers followed by non-exerted stigmas later in the truss. In the F3 generation, the entire shaft of the stigma is exposed in these early flowers.

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Re: Micro dwarf x Indeterminate cross ideas.

#265

Post: # 142429Unread post bower
Wed Jan 08, 2025 7:23 am

I can only venture to guess that the distance from the lights might play a part in how well they shed pollen, although there is not a lot of height difference in those plants so maybe not. But considering that the soil is watered therefore higher RH close to the ground, vs the later flowers which are lifted highest on the plant, in the lowest RH situation closer to lights, it might be a factor.
OTOH for parthenocarpics it may be normal that earlier fruit are seedless, with seeds being produced late. That was more or less the pattern I saw with Siletz, and perhaps such patterns are more genetically determined than I thought. We assume they are doing this to cheat early spring environment factors, but maybe it's genetically selectable?
And then again, maybe most likely of all, the plants decide whether to make seeds or not based on their maturity status.
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Re: Micro dwarf x Indeterminate cross ideas.

#266

Post: # 143627Unread post KaguyaCloud
Sun Jan 26, 2025 1:02 pm

Update 1/26/25:


This will probably be the final update for the Joro F3 generation before doing another round of backcrossing. Overall the yield data is relatively good.

Joro F3-1 has tasty fruit, although more diluted than the F2. Growth habit is noticeably larger. Yield so far is 353.36g(12.45oz) after harvesting 67 fruits.

Joro F3-2 has fruit with just a slight amount of flavor, but it is still quite bland compared to the F2 parent. Growth habit seems to be very similar to it's micro parent. Yield so far is 304.05g(10.73oz) after harvesting 64 fruits.

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Re: Micro dwarf x Indeterminate cross ideas.

#267

Post: # 143636Unread post Doffer
Sun Jan 26, 2025 1:50 pm

Do u think u lost a micro gene in Joro F3-1?

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Re: Micro dwarf x Indeterminate cross ideas.

#268

Post: # 143642Unread post KaguyaCloud
Sun Jan 26, 2025 2:10 pm

Doffer wrote: Sun Jan 26, 2025 1:50 pm Do u think u lost a micro gene in Joro F3-1?
Joro F3-1 had a very similar growth habit to the F2 parent, so I don't think a micro gene was lost. But, F3-2 is smaller than both the parent and F3-1, which likely hints that the F2 parent might have been heterozygous for another micro gene. This recessive gene involving smaller stature might be related to root morphology/length during germination.

I've noticed that Orange Hat, Jochalos, and Micro-Tina exhibit short root length that tend to form a spiral shape as it grows in the germination chamber. And I know that larger micro varieties such as Vilma do not have this trait(it has short roots, but does not spiral around). F3-2 seems to have expressed short root length just like the other micros and exhibited a more stunted growth habit.

I will be able to determine if this is true through growing out the F2 seeds to figure out the trait segregation.

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Re: Micro dwarf x Indeterminate cross ideas.

#269

Post: # 143895Unread post KaguyaCloud
Wed Jan 29, 2025 8:44 pm

Found another interesting article relating to seedling traits in Micro-Tom.
https://pmc.ncbi.nlm.nih.gov/articles/P ... %20%5B5%5D.

When they applied a brassinosteroid hormone to the seedlings, the root length, height, and overall mass increased significantly.
https://www.ncbi.nlm.nih.gov/core/lw/2. ... 6-g001.jpg

This might indicate that root size might be an early indicator of being deficient in a certain brassinosteroid hormone, and therefore a possible micro trait. However, smaller root size isn't entirely an indicator of having a dwarf gene, as some of the root systems of my micro project exhibit normal growth.

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Re: Micro dwarf x Indeterminate cross ideas.

#270

Post: # 143973Unread post KaguyaCloud
Fri Jan 31, 2025 12:21 am

After going back and forth in ideas with the Gemini AI, it lead to a very interesting theory on the unique architecture of Micro-Dwarfs. In typical tomato plants, there is a vegetative cycle in the primary(main) and axillary(suckers) shoots before the plant begins growing the flowering portions called sympodial shoot meristems. This of course, is the flower truss followed by 2-3 leaves and so on depending on indeterminate/determinate growth habit.

However, in micro-dwarf tomatoes, the axillary shoots only grow determinate sympodial shoot meristems without the vegetative cycle. In addition, the primary shoot terminates oddly early for a normal determinate plant. I will quote verbatim:
Typical Determinate Growth: In a typical determinate tomato, the primary shoot grows vegetatively for a certain period, producing leaves, before transitioning to reproductive growth and terminating in a flower cluster. The axillary shoots then take over, each one also growing vegetatively for a bit before terminating in a flower cluster. This repeating pattern of vegetative growth followed by reproductive termination is what defines sympodial growth.
The Special Case: In your special determinate plant, the primary shoot terminates very early. The hypothesis is that this early termination isn't just a premature end to vegetative growth, but rather that the primary shoot is already acting like a sympodial unit from the start. It's as if it's saying, "I'm going to do my short bit of vegetative growth (8 leaves), then I'm done (2 inflorescences)."
Irregular Sympodial Meristem: So, the primary shoot isn't typical for a determinate plant, but it's also not behaving like the typical vegetative growth of a sympodial unit. It's doing something in between: short vegetative growth, then termination. This is why we might call it an irregular determinate sympodial meristem – it follows the pattern of sympodial growth (vegetative then reproductive termination), but it's doing it on a compressed timeline and with a unique leaf count.
Why This Matters: If this is true, it means the genetic change in your plant isn't just affecting the timing of flowering, but it's fundamentally altering the identity of the primary shoot meristem. It's making it behave, in a developmental sense, more like a sympodial meristem from the very beginning, even though its growth looks different from the later sympodial units (the axillary shoots).
I never thought to consider that the primary shoot might have been a slightly modified sympodial meristem itself, but it makes sense considering the resulting generations of my project. By assuming that there is no "true" vegetative cycle and that the primary stem was actually a sympodial shoot meristem, that would explain why certain micros suddenly terminates to 2 flower clusters. It is possible that it is developmentally just like the axillary stems without the initial flower trusses that would typically grow from there.

By crossing the micro with a vigorously branching indeterminate and selecting for growth habit in the F2 generation, the resultant dwarf F2s and F3s exhibited two side shoots growing from the cotyledons with seemingly no primary meristem. This could be caused in several ways:

1) It's possible that the genes in the indeterminate parent has a strong ability to initially grow a primary shoot that had a vegetative cycle before growing the sympodial shoots. However, if we assume that micros are only capable of growing just the sympodial shoots, then there's a slight genetic incompatibility, with a loop hole. If there is a strong requirement to grow a vegetative cycle before flowering, then maybe it will terminate immediately at the cotyledons, then grow the sympodial shoots from there. This would explain why all shoots growing from the cotyledons behave like their own micro plant.

What's strange is that this also applies to the Red F2 as well, which was an indeterminate dwarf. For clarification, the red F2 did develop side shoots that had a normal indeterminate growth habit with a normal vegetative cycle and sympodial shoot meristems. It did grow a primary shoot, but that shoot terminated after 2 leaves grew, leading 2 axillary shoots to grow out. Even when the F2 had the ability to grow a vegetative cycle, the vegetative of cycle of the initial primary shoot suddenly halted. This leads to an idea of another trait that only hinders the vegetative cycle of the primary shoot and a separate trait that inhibits the vegetative cycle entirely.

2) The extreme branching trait of the indeterminate plant lead to branching at the cotyledon stage. The indeterminate Rosella cherry is capable of growing another axillary shoot from an existing axillary node, even after it's been pruned. If we assume that the micro parent only grows one shoot due to lack of branching genetics, then introducing genes that involve high incidence of branching might lead the tendency to grow more than one primary shoot without an initial vegetative cycle.

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Re: Micro dwarf x Indeterminate cross ideas.

#271

Post: # 143989Unread post bower
Fri Jan 31, 2025 7:33 am

Interesting...
I know from prior reading that the number of leaves in the vegetative stem before flowering is under separate genetic control to the pattern that follows. So the reasoning here would be that the genes involved in the vegetative stem are completely suppressed.

I should mention that I 've seen this pattern in determinates (non micro, for example Jagodka is one that comes to mind).
Axillary shoots in this case repeated the entire pattern of the vegetative stem with termination of two clusters.

In some determinates, the number of leaves in axillary shoots may be fewer before termination.
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Re: Micro dwarf x Indeterminate cross ideas.

#272

Post: # 144050Unread post KaguyaCloud
Fri Jan 31, 2025 9:34 pm

bower wrote: Fri Jan 31, 2025 7:33 am I should mention that I 've seen this pattern in determinates (non micro, for example Jagodka is one that comes to mind).
Axillary shoots in this case repeated the entire pattern of the vegetative stem with termination of two clusters.
So there were no flower clusters except at the very end of the axillary shoots? Did the main stem grow like a typical determinate? I just looked through "Pippin's family photos 2021" thread and the amount of variation in early determinate varieties is a lot more staggering than I thought.
Last edited by KaguyaCloud on Fri Jan 31, 2025 9:38 pm, edited 1 time in total.

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Re: Micro dwarf x Indeterminate cross ideas.

#273

Post: # 144052Unread post bower
Fri Jan 31, 2025 9:37 pm

Main stem was (iirc) 7 leaf axils and two cluster terminal. Side shoots likewise, 7 leaves, 2 clusters.
The main stem did not put on a shoot after the terminal, as many do. So that was it.
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Re: Micro dwarf x Indeterminate cross ideas.

#274

Post: # 144053Unread post KaguyaCloud
Fri Jan 31, 2025 9:56 pm

bower wrote: Fri Jan 31, 2025 9:37 pm Main stem was (iirc) 7 leaf axils and two cluster terminal. Side shoots likewise, 7 leaves, 2 clusters.
The main stem did not put on a shoot after the terminal, as many do. So that was it.
That's quite an interesting growth habit. Perhaps those shoots might be a modified sympodial shoots as well, but expressed in a different fashion. Weirdly enough, 6-7 leaves is about the same number of leaves in a typical terminating determinate micro pattern(usually a strong axillary shoot). I wonder what happens if it were to be crossed with a dwarf or indeterminate plant.

Although, like you said, the number of leaves in the axillary shoots may vary depending on the variety.

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Re: Micro dwarf x Indeterminate cross ideas.

#275

Post: # 144066Unread post bower
Sat Feb 01, 2025 7:56 am

The number of leaves before first cluster is genetically distinct from other growth habit genes, but it is also to some extent subject to environmental influences. 7 leaves to first cluster is very typical of tomato plants of all kinds in my environment. There are exceptions with more than 7. On one occasion, I have seen one of the plants that is usually a 7 go to 8 instead, which I attribute to environment that season. I've also heard other people report of having 3 or 4 leaves only before flowers begin, on same named varieties - I don't know whether that difference is genetic or environmental. Jagodka is one of the plants I've heard of having fewer leaves before flowers in someone else's grow. But there are multiple strains of Jagodka circulating afaik.
The one I had was a very small plant with the sourest fruit I've ever tasted.
I might even revisit that one, for the project of breeding a tomato substitute for lemons.
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