Micro dwarf x Indeterminate cross ideas.

[bower]

I don't have a lot of experience with micros, but I can tell you it's fairly common for determinates, that after terminating their cluster pattern they will make an axial shoot off the terminal end which then goes through their "leaves to first cluster" number, and then repeats the terminal pattern. As if you had two terminated determinate plants on top of one another. I've seen it in OP's as well as crosses.
IDK how much environmental effects play a part in that, but I've seen it pretty commonly here. Since your growing conditions are so tweaked for speed breeding, that might be a factor as well.
Also noted that in determinate-indeterminate crosses, termination patterns are highly variable and they do segregate and eventually become stable, but tall plants that repeat their determinate pattern are a common product from that type of cross.

[KaguyaCloud]

I don't have a lot of experience with micros, but I can tell you it's fairly common for determinates, that after terminating their cluster pattern they will make an axial shoot off the terminal end which then goes through their "leaves to first cluster" number, and then repeats the terminal pattern. As if you had two terminated determinate plants on top of one another. I've seen it in OP's as well as crosses.
IDK how much environmental effects play a part in that, but I've seen it pretty commonly here. Since your growing conditions are so tweaked for speed breeding, that might be a factor as well.
Also noted that in determinate-indeterminate crosses, termination patterns are highly variable and they do segregate and eventually become stable, but tall plants that repeat their determinate pattern are a common product from that type of cross.

Ah I think I finally understand what you meant after reading this article: https://journals.biologists.com/dev/art ... -regulates.

I did not know that regular determinates for their main stem actually produce a pattern set of flowers and leaves before terminating at at two flower clusters(See: https://openi.nlm.nih.gov/imgs/512/17/3 ... rds=arrest). Each leaf and flower cluster is called a sympodial unit apparently. The main stem of micro dwarfs, from what I have observed, terminate exactly at 2 flower clusters once they've grown enough leaves to mature with no other flowers and leaves in between. This means that they have zero(or one?) sympodial units in the main stem instead of the classic 3 that determinates have However, their axillary shoots actually behave like what a regular determinate variety would behave(For Jochalos it seems that there are 3, but only 2 for Micro-Tina). I am somewhat shocked.

I have photoshopped what the micro dwarf shoot architecture looks like compared to a regular indeterminate and determinate(https://imgur.com/a/A1ORyBS).

So this must mean that there is a gene in micro dwarfs that allow for the varieties to terminate earlier at the apical/main stem. But this gene does not get regulated for axillary side shoots/suckers. It might be one of the defining things that we can use to determine whether or not a plant is micro dwarf. Thank you for providing your valuable insight.

[bower]

That's a really nice diagram of the sympodial repeat patterns.
When you cross determinate and indeterminate, the number of sympodial repeats is highly variable in the F2, with a small minority retaining the compact growth habit, in my experience. So whatever gene or genes restrict the number of repeats, appears to be recessive. (Environmental factors that promote tall growth can also mess with your results, to an extent, making it tricky to select away from the tendency to keep on growing.)

[KaguyaCloud]

That's a really nice diagram of the sympodial repeat patterns.
When you cross determinate and indeterminate, the number of sympodial repeats is highly variable in the F2, with a small minority retaining the compact growth habit, in my experience. So whatever gene or genes restrict the number of repeats, appears to be recessive. (Environmental factors that promote tall growth can also mess with your results, to an extent, making it tricky to select away from the tendency to keep on growing.)

In that case, it would probably be helpful to select towards the progeny that terminate earlier in my situation as a means to avoid high amounts of variation. Due to my limited space, I will have to do it pretty slowly even if I consider the 3 week seed to flower time.
Strangely enough, I found an article that crossed an indeterminate tomato "M82" with Micro Tom(https://www.plantbreedbio.org/journal/v ... &&vmd=Full) and it seems that the resulting F1 M82xMicro Tom cross exhibits an intermediate size and flowering architecture between the parent varieties. This might mean that there might be a trait or traits that are co-dominant in terms of size and fruiting characteristics.

Usually environments that promote taller growth or stem elongation is usually the ratio of lights hitting the plant at any given time. Low amounts of light or photons that promote stretching(far red and green) usually cause this issue. Luckily I am able to keep a decently consistent amount of light hitting the plants at any given time, and my Micro Dwarf's are actually growing significantly shorter than the pictures I've seen. In addition, it doesn't seem like pot size affected how long the internode lengths are. The internodes between a 6 inch pot Rosella Cherry is as long as the internodes of a 2 inch filled 4 inch pot Rosella Cherry.

But, like you mentioned, plant height can vary depending on growing conditions. It's one of the reasons I really am hesitant to measure is overall plant height. My tests and experiments may not reflect on other growing conditions. But since I have a reference on what the leaf, flower, and internode lengths are in my growing space, I think those might be better to compare to when I start growing out the F2s.

[KaguyaCloud]

Update 1/23/24:
Jochalos and Vilma are still doing okay.
https://imgur.com/a/WmhFFec

I read forgot to put in my metrics for recording the time of flowering from planting. So I will define some things that I do:
I germinate my seedlings in a plastic food container under my grow lights. The plastic container is disinfected with soapy water and then sprayed with 70% isopropyl alcohol, then dried. This is to decrease the chance of mold growth.

Inside the plastic container, I line it with a folded paper towel with a piece of magazine paper on top. This is to avoid the roots from anchoring and growing into the paper towel. Then I saturate the paper towel with water to the point where a thin pool of water has formed in the bottom. I place the magazine paper on top. The seeds are then placed on top of the magazine paper. In this image, Jochalos is on the top and Vilma is on the bottom: https://imgur.com/a/g0OfeGZ. Jochalos has a weird germinating behavior, the root corkscrews when it germinates. I germinated some Orange Hat and Micro Tina seeds I collected to compare, but they didn't exhibit this root growth behavior.

I wait until the first two cotyledons develop and open up before I plant them into the soil. I can wait until most of the seeds germinate and grow cotyledons before planting for consistency(in general, it takes around 5 days after roots start poking out of the seed in my conditions). The seedlings at this stage can be kept in the chamber for several weeks before planting assuming that the seeds and chamber are disinfected.

Rosella Cherry(indeterminate):
Planting date: 11/19/23
First flower: 12/21/23
First ripe fruit: ???(First 4 flowers were destroyed due to pollination collection experimentation, but it will likely be several days or weeks later than normal)

Jochalos(micro):
Planting date: 12/3/23
First flower: 12/29/23
First ripe fruit: ??? I expect around at day 65 to harvest my crossed tomato or until 2/6/24

Vilma(micro):
Planting date: 12/3/23
First flower: 1/1/24
First ripe fruit: ???

[bower]

Is there a tweak to the lighting setup for ripening? Or already sufficiently optimized for that, with a bias towards 'warm' end of the spectrum.

[KaguyaCloud]

Is there a tweak to the lighting setup for ripening?

I do not think I have fully optimized the ripening aspect of the set up. However, I fertilize using the same hydroponic nutrients(MaxiGrow, 37.8g powder 5 gallons of water or 10g/L) and the same lights(Monios T8 2ft white light) throughout the entire growing period.

I didn’t know that light spectrum affected ripening time. My main focus is light quantity for the most part(30moles per m2 per day). I was under the impression that temperature was more important in that aspect.

[bower]

No there's definitely a wavelength tweak towards the red end of the spectrum for ripening that I've read about. I considered it when buying bulbs - I went for the blue end instead (with the old fluorescents) which is maybe best for greens. I use a couple of shoplights that are more of a mid value is it 4000K? or 5000. and they are okay for greens too but have some dwarfing effects possibly due to the narrow spectrum in the LED. They aren't great for tomatoes or peppers. So I need new lights and will be looking for a spot in the budget for that as the winter goes by. Not much of a lighting nerd but I will have to try something.
Hmm... here's something new about postharvest effects of LEDs on ripening - different for tomatoes than some other fruits, who knew!
https://felixinstruments.com/blog/leds- ... t-quality/
"Blue light hinders the ripening process and softening of tomatoes, while red LEDs promote the ripening process. So blue can extend shelf life and red speeds up ripening."
Here's some other recent work: a vote for blue light
Supplemental Blue Light Frequencies Improve Ripening and Nutritional Qualities of Tomato Fruits
https://www.frontiersin.org/articles/10 ... 88976/full
And this one used red in the morning and blue in the evening I think? Anyway, also affecting nutritional quality and taste.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8841748/
So I think playing with ripening frequencies is something you might want to try. Make a note of your results with the present lights, and what spectrum it is, and another time you can check on the difference in ripe time or maximize taste parameters for an F2 grow.

[KaguyaCloud]

How far would you say your plants are from your shop lights and what is their wattage and length? Light is a finicky thing, the intensity can decrease by 50% when you double the distance away and increase by 200% if you half the distance. This means that it doesn’t scale linearly at all with distance.

For my lights these were the measurements I have at three distances from the center of the light:
4cm away: 38,000 lux
9cm away: 16,400 lux
18cm away: 7,750 lux

I did a bunch of measurements regarding optimal light distance and the ideal distance for my lights is around a 4-6cm away. You should aim to have 30,000-40,000 lux or more at the top of your canopy.

I just read that study with blue light on the effects of ripening. So it’s suggested that ripening of up to a 4 day difference could be achieved with supplemented blue light. However, is it the fact that they supplemented light that increases the ripening time rather than the spectrum they used? I wish they used white or red LEDs as another control time see if the spectrum mattered.

But it probably isn’t too surprising to see that adding more photosynthetic light speeds up the process of ripening since there’s more energy available to further metabolize sugar and aromatic molecules.

For the second study about light supplementation during the morning and evening, that’s pretty interesting. Plants do have an internal clock and it’s likely their metabolic pathways differ depending on the time of day. With plants grown completely indoors, I wonder how that would effect the quality of the tomatoes.

[Doffer]

Unripe fruits that fall from the plant can be allowed to ripen and the seeds are fertile.

Now I wonder how many days after pollination you can remove the unripe fruit from the plant and let it ripen in a warm container (+25C) with ethylene?

This could accelerate the ripening process even more due to the Ethylene and the high temperature.

[KaguyaCloud]

Now I wonder how many days after pollination you can remove the unripe fruit from the plant and let it ripen in a warm container (+25C) with ethylene?

It looks like you can remove the unripe fruit once it hits the breaker stage:
https://extension.psu.edu/is-this-tomat ... e%20fruit.

"It is also at the Breaker Stage that the tomato receives no additional nutrients from the plant. In fact, a skin will form between the plant stem and the plant, effectively cutting off nutrients from the plant to the fruit."

[KaguyaCloud]

@bower Quick question. Is it normal for the axillary shoots of determinate tomatoes to skip the “leaves to first flower” pattern and jump immediately to the termination pattern of the sympodial repeats?

If not, the growth pattern of micro tomatoes are even more strange. Termination to 2 flower clusters in the main stem without sympodial repeats, axillary shoots that skip to immediately growing the sympodial repeats instead of growing 8-9 leaves before flowering. It feels that the growth pattern is somehow reduced by a significant amount compared to regular determinate and indeterminate varieties.

I found an article relating to a specific gene that can cause early termination, similar to the one I photoshopped for the micro architecture.:
https://sci-hub.ru/https://pubmed.ncbi. ... /22525246/

Conversely, over-expression of SFT induces precocious primary-shoot termination (after 4–6 leaves), but the sympodial program is largely unaffected, demonstrating that the primary and sympodial apices have different sensitivities to SFT


For example, over-expression of SFT and FT in day-neutral tomato and tobacco resulted in plants displaying fewer leaflets per compound leaf, shorter internodes, and thinner stems [17,37]. Conversely, sft mutants of tomato lose the reiterating pattern of determinate sympodial units with three leaves and terminal inflorescence (flowering truss) and instead have a single monopodial vegetative inflorescence with leaves and periodic flowers [17].

Very interesting. This explains a lot of characteristics of micro tomatoes. They might be over expressing SFT(Tomato Florigen). After looking at tomatoes with the 35S:SFT gene, it looks awfully similar to a Micro Tom without the d gene(smooth leaves, suppressed secondary leaflet growth). Maybe this is related to one of the genes we need to select for on micros.

[bower]

Now I wonder how many days after pollination you can remove the unripe fruit from the plant and let it ripen in a warm container (+25C) with ethylene?

It looks like you can remove the unripe fruit once it hits the breaker stage:
https://extension.psu.edu/is-this-tomat ... e%20fruit.

"It is also at the Breaker Stage that the tomato receives no additional nutrients from the plant. In fact, a skin will form between the plant stem and the plant, effectively cutting off nutrients from the plant to the fruit."

There is a stage before 'breaker', that is 'green ripe'. Any fruit that reaches 'green ripe' stage can be ripened off the vine.

[bower]

@KaguyaCloud Quick question. Is it normal for the axillary shoots of determinate tomatoes to skip the “leaves to first flower” pattern and jump immediately to the termination pattern of the sympodial repeats?

Think of three growth habit features which are under separate control:
1) The number of leaves to first flower
2) The sympodial repeat pattern
3) The number of sympodial repeats

I noticed earlier in a diagram you posted, that the number of repeats for a determinate was given as three. This number belongs to whatever example (variety) was given. In reality the number of repeats can be any number from 1 to (never stopping).
When the number is one, the plant has to go through the 'number of leaves to first before it repeats the sympodial pattern.
When the number is (unlimited), the plant will continue to repeat until season end or something else takes it down.

If the number is, for example, 3, there will be 3 sympodial repeats, then the number of leaves to first, then a repeat of the 3 sympodial repeats.

Caveat on all growth habit issues is the influence of environment. The sympodial pattern itself is variable and in some circumstances a different pattern can emerge, even in a line that appeared to be very stable for that pattern. Environment can also affect the number of leaves to first flower. Saw that last year.

[KaguyaCloud]

For clarification just so that we are on the same page.
Determinate plants can exhibit these sets of growth patterns:

Main shoot:
Leaves to first flower(8 leaves for example)
Sympodial repeats that end in two clusters of flowers that can have variable patterns of flower and leaves before termination.

Axillary shoot/sucker:
Leaves to first flower
1 to unlimited sympodial repeats depending on the variety and growing conditions.

Is it a correct assumption that determinate plants can have indeterminate-growing axillary shoots?

For the micro dwarf growth, I observed this:

Main shoot:
Leaves to first flower.
No sympodial pattern. 2 flower clusters grow after leaves to first flower is reached.

Axillary shoot/sucker:
No leaves to first flower observed.
Shoot growth starts at variable sympodial repeats on the same plant.

[bower]

Yes to the determinate characters you listed.

Is it a correct assumption that determinate plants can have indeterminate-growing axillary shoots?

No. Meaning to say, they will not have the indeterminate pattern of 3 leaves, cluster, 3 leaves, cluster and so on. The axillary shoots normally go through the same number of leaves as primary shoot, then end in sympodial pattern. Thinking side shoots from a single main stem. They can also do multiple sympodial repeats, or put out a shoot from a terminal axil to do it again.

I have seen some really wierd F2 growth habits though - notably main stem appearing to be indeterminate, but side shoots proved to be determinate in the sympodial pattern. I spent a bit of time taking a close look at growth habit variation when I started working on indet X det crosses, but there's nothing simple about the segregation, and even when you think they're settled, some environmental trigger and they will still surprise me. So it's quite a rabbithole and worth looking at but I just accepted they will surprise me at a certain point.

[KaguyaCloud]

Understood. The axillary shoots have the ability grow it's own axillary shoots and so on.
It looks like I will have to record down the axillary shoot growth of the crosses. Based off the weird growth habits you have described, it looks like axillary shoots really are unpredictable. I wonder if apical dominance or being heterozygous for sp has to do with these inconsistent patterns for determinate crosses.

[bower]

Hmm apical dominance. There's a trait I don't know much about.
There are definitely more traits or modifiers involved in growth habit than what we have discussed.
The wierd F2 which I described, with the indeterminate main stem, was seed saved and grown out, and all offspring were sp/sp.
The indeterminate parent was Black Cherry. A particularly difficult parent for determinates, with strong tendency to be very long vines, long internodes, strong responses to environmental cues to get long, etc. Subsequent generations continued to tend to be large and leggy plants, in spite of the defining sympodial patterns of determinate parent.
So in hindsight, or in your situation breeding micros, I would choose the indeterminate parent carefully to avoid those tendencies. More compact indeterminates, or dwarf and/or determinate parent, would likely be easier to bring back to the goal.
OTOH if you don't mind stirring the pot, you can cross your cross to another plant with desired growth habit traits to bring them back. This is what I did in the end, made multiple crosses with other determinates. Still lots of large determinate plants from those crosses, however.

[KaguyaCloud]

Worst case scenario, I’ll end up needing to backcross to the micro parent. Rosella cherry is a very vigorous and tall variety just like black cherry.

I think one of the issues with crossing indeterminate and determinate is having less cues to work with until flowering occurs. I suppose lengthened internodes must be part of another chromosome, maybe chromosome 2(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6540210/). If that is the case, there is at least a 1 in 16 chance that an F2 plant would be both compact as a parent and determinate.

I might still be able to manage if I heavily cull off any plants with sympodial patterns, non-rugose leaves, and a 7 leaflet structure. Chromosome 2 also contains the dwarf gene, so there is one easy tell at least. There could potentially at least a 1 in 112 odds to have a micro trait(1 in 28 multiplied by 1 in 4 to get sp).

I plan to plant a small number of them at a time, select towards a specific leaflet growth pattern, observe at least the first 3-5 leaves, then record down traits just to see what the odds are that I’ll get the traits I desire.

Breeding the plants indoors and segregated from the other plants also gives another level of control to prevent any cross pollination. I’m mainly curious on statistical chances and seeing just how difficult micro traits can segregate out just from early visual cues.

[bower]

I'm looking forward to that! Early cues are great.
Also loving the enhanced potential for fast generations in the indoor grow.