Micro dwarf x Indeterminate cross ideas.

[KaguyaCloud]

Strangely enough, one of the strategies of selecting towards micro traits from the papers I’ve read is just by hypocotyl length alone(https://www.sciencedirect.com/science/a ... 6-p09alVFV). I don’t think I have the bravery to do that, plus I’m curious on what traits are segregated in the F2 generation.

Although, I could sprout some micro seeds as a control. The first two true leaves of the F2 should be sufficient to determine the leaf pattern regardless.

[KaguyaCloud]

Update: 1/27/24
Images here: https://imgur.com/a/fKWPqcn

I got a surprise from my Orange Paruche tomatoes, the fruits are already started past the breaker stage.
It has been only 61 days since I have planted them from the open cotyledon stage and they have already began ripening yesterday. That is more ludicrous of a timeline than I expected from an indeterminate variety, especially considering that the conditions are actually not that optimal(they get less light in the weekends because I turn them on later in the day, horizontally teasing the vine would have given more light but I had no room).

It also seems like the Jochalos fruit that I have crossed pollinated 12/27/23 is starting to get into the breaker stage of ripening. If so, it has been exactly 55 days since I have planted them into my container. But I might wait until the shade turns more orange before harvesting the seeds.

[bower]

Those are impressive days to ripe.
It is best to let the fruit ripen completely for optimal seed quality/longevity.
However, for fastest turnaround on an F1 some people have planted seeds of fruit barely ripe and they say it does fine when planted immediately. According to what I've read, the only concern is that they may not remain viable for years as other tomato seeds do.
I always let mine mature fully, because I want seed in my stash to go back to, just in case. For the sake of a couple of extra days to ripen, it wouldn't make sense to risk that. But it isn't the same context as the speed breeding.

[Doffer]

especially considering that the conditions are actually not that optimal(they get less light in the weekends because I turn them on later in the day, horizontally teasing the vine would have given more light but I had no room).

Once the fruits have set, the hours of light are less important. The higher temperature is much more important for faster ripening. A few studies show that fruits actually ripen faster with fewer hours of light.

This paper shows, earliness is increased with less hours of light. But the ripening is only a few days different.
https://edepot.wur.nl/20530

12H: Exposure time 12 hours, Light intensity 162μmol/m2.s (12,500Lux), Light sum 7mol/m2.day
15H: Exposure time 15 hours, Light intensity 162μmol/m2.s (12,500Lux), Light sum 8.8mol/m2.day
18L: Exposure time 18 hours, Light intensity 135μmol/m2.s (10,400Lux), Light sum 8.8mol/m2.day
18H: Exposure time 18 hours, Light intensity 162μmol/m2.s (12,500Lux), Light sum 10.5mol/m2.day
The 24h temperature was kept as similar as possible for all treatments. Although I understand from the data that the high intensity (162μmol/m2.s) have slightly greater DIF (difference in temperature between day and night). This was necessary to get a more generative crop.
It was 14C at night and 24C during the day and the 24-hour average temperature was 19.2C.

Ripening fruit after flower formation 12H at 63 days
Ripening fruit after flower formation 15H at 62 days
Ripening fruit after flower formation 18H at 65 days
Ripening fruit after flower formation 18L at 67 days
So a total of 5 days difference and short exposure means faster ripening.

[KaguyaCloud]

According to what I've read, the only concern is that they may not remain viable for years as other tomato seeds do.
I always let mine mature fully, because I want seed in my stash to go back to, just in case. For the sake of a couple of extra days to ripen, it wouldn't make sense to risk that. But it isn't the same context as the speed breeding.

If that's the case, I suppose I will wait another 10 days before harvesting the seeds. I do value the ability to go back and grow out my F1 in case an emergency happens or if I cannot clone it for any reason.

Once the fruits have set, the hours of light are less important. The higher temperature is much more important for faster ripening. A few studies show that fruits actually ripen faster with fewer hours of light.

Interesting study. For the fruits specifically, mine actually grew past the height of the grow lights, so they actually are getting a measly 1,600 lux from a neighboring light much further away. And I'm not sure if I can control that factor for the micro dwarf's either since their canopy can completely cover the fruits.

[KaguyaCloud]

Update: 2/21
I got COVID and am currently recovering. And on top of that, I lost my sense of taste for a few weeks right when the tomatoes I grew started to ripen. However, my sense of taste is fully recovered(I didn't lose my sense of smell, which I am grateful for) for the most part and I have taste tested all my tomatoes I've grown so far.

Here is a photo update: https://imgur.com/a/2kQpfin

My F1 seeds germinated and I currently have them planted in a pot of soil that is coconut coir hydrated in nutrient solution and mixed with perlite in a 3:1 ratio of coir to perlite.

Here are the flavor profiles of all the tomatoes I have grown:

Rosella Cherry: Pretty sweet, little to no acidity, the aroma is kind of fruity. There are no off-flavors and it has a satisfying lingering aftertaste with thin skin. It is doing very well in it's 1 inch of soil. I'm likely going to cultivate cherry indeterminates using my miniaturization technique. Yields are pretty low per unit area, however.

Orange Hat: This micro is very inconsistent in flavor in my personal experience. It can have a good balance of sweet and acidic when it ripened to the point where it is neon orange. At best Orange Hat has a citrus/grassy aroma with a very satisfying lingering umami flavor. However, it has very thick skin and can taste strongly grassy and astringent.

Jochalos: Tastes acidic to neutral to me and has a the flavor profile of what tomato leaves smell like. It's similar to orange hat, but with less umami. The skin is kind of thick. Update 2/25, the riper tomatoes have a some-what satisfying lingering musky/vanilla-like aftertaste

Vilma: Honestly, it tastes almost exactly like a store bought tomato. It's pretty neutral tasting. It's not sour and it's only the tiniest bit sweet. Having thin skin is a plus.

Micro Tina: No sweetness and relatively bland. The first thing that I tasted was an astringent flavor somewhat similar to the smell of pine needles. Thick skin as well.

There is only one thing that I have learned from this experience, and it's that micro dwarfs are in dire need of improved flavor via breeding. I have grown my micro with my indeterminate Rosella cherry, however the Rosella were grown in even less than ideal conditions(1 inch of potting mix, 2 bars of light instead of 3) and still tasted a magnitude better than all of my micro dwarf tomatoes combined.

I do not think I will hybridize any varieties together and will instead repeatedly backcross my Jochalos x Rosella Cherry cross with Rosella Cherry as the parent. It will take a very long time because I need to select towards micro dwarf as a phenotype, but I think it's worth the effort in my own opinion.

[bower]

Glad to hear you got your sense of taste back. I appreciate your taste reviews!

[KaguyaCloud]

Update 2/23/24:
I have good news! It seems that my cross was successful and my seedlings have finally sprouted out of the soil. I have compiled a more ordered documentation on my process of harvesting the F1 seeds to first 2 cotyledons.

https://imgur.com/a/WCzJW7V

Luckily on my end, I am able to tell if a cross is successful based off the roots that grow at germination. Jochalos has a unique seedling root structure as seen here. I didn't know if the gene was dominant or recessive, but it seems to be recessive based off the cross:
https://i.imgur.com/xO5e7iY.png

As @Doffer mentioned, tomatoes that are homozygous with the dwarf gene do not close their cotyledons at the end of the day. Jochalos did not close it's leaves at the seedling stage at the end of the day, but the F1 progeny did. Therefore, the cross is likely to be successful.

The first photo of the cotyledons were taken at 5:10pm and the close up shot of the closed cotyledons were taken at 9:33PM. We may be able to isolated the dwarf(d) gene at the seedling stage if that is the case.

Here's the timeline:
12/03/23: Planted Jochalos seedlings.
12/27/23: Performed demasculation of Jochalos flower and crossed with Rosella Cherry pollen.
2/4/24: Harvested ripe fruit and seeds(63 day generation time).
2/19/24: Began germinating seeds.
2/21/24: Seeds germinated and planted into potting soil.
2/23/24: First cotyledons opened up. I will use this date as the start date to remain consistent with my past data.

[Doffer]

Very interesting, so in 70 days you can breed a new generation.
Let say 7 days for germanation seeds, you don't have to ferment them. Allowing the seeds to dry with gel on a paper for an hour is sufficient before sowing them.
And then after germination another 63 days until harvesting the fruit.

[KaguyaCloud]

Update: 2/26/24
I have smelled of the leaves of the cotyledons of the F1 hybrid by rubbing my fingers on the leaf and have concluded that the leaf smell is almost identical to the young leaves of Rosella Cherry, which is a grassy chocolate-like aroma. Jochalos on the other hand has a very citrusy smell that is similar to that of an orange peel. I have noticed that Orange Hat and Orange Paruche(indeterminate F1) also have that citrus-like aroma to their leaves. I wonder if the smell of the leaves correlate with the flavor profile of the fruits.

At the very least, it seems that the genes related to leaf smell in Rosella Cherry is dominant compared to the citrus notes of Jochalos.

[KaguyaCloud]

2/28/24
If has been 5 days since the JoRo(Jochalos x Rosella Cherry) F1 has began to grow out the second leaf.
Images found here: https://imgur.com/a/KmFwgQV

The leaflet patterns seems to be as follows: 3, 5-

Based off of this pattern, I am going to hypothesize that this will follow Rosella's leaflet growth pattern(3, 5, 7, 7..). This would mean that the gene for the leaflet pattern is dominant towards Rosella. But I will do further leaf observations to see if that is true. It could just as easily be a 3, 5, 5, 7, 7 pattern like Vilma. And if it is, that must mean that there is a dominant micro-dwarf gene in Jochalos that causes the leaf reduction at the third leaf.

If what has been observed is true, then I can potentially select micro-dwarf seedlings based off of leaf patterns in the first 5 days after the cotyledons have opened up. The seedlings at 5 days are measured at 7cm(tip to tip at the cotyledons) by 4cm(length between first two leaves) by 5-6cm(height).

I could theoretically plant 20-40 F2 seedlings at a time with 4 seedlings fitting in 5-10 4 inch pots. Then I can plot the probability of certain traits popping up. According to all the literature I've seen this far, there is a 1 in 28 chance that a micro dwarf trait pops up when crossing a micro dwarf with a normal determinate variety. However, they did not specify which traits exactly they selected towards other than hypocotyl length. Since I'm working with an indeterminate variety, the chances of getting a micro phenotype regardless of indeterminate or determinate is 1 in 28. However, the chances of getting a determinate micro is 1 in 112 chance. Not terrible odds all things considered.

I'm stumped at the mathematics of it. A chance of 1 in 28 isn't a ratio that is typically expressed by pure recessive traits(mainly it's 1 in 4, 1 in 16, 1 in 64). In fact, that ratio is expressed by exactly 2 recessive and 2 dominant traits(1/4 * 1/4 * 3/4 * 3/4 = 9/256 = 1/28) that's independent of the sp gene.

So, if that's the case, then the only recessive traits we can confirm that makes micro dwarfs micro is just the dwarf gene.
The dwarf gene alone does not reduce leaflet numbers, however.
And since we're some-what sure that the gene to reduce leaflet number may be recessive or co-dominant from the F1 cross, this is likely the last recessive gene in according to the statistics. And to top it off, this gene isn't entirely necessary to make micro dwarfs micro since micros like Vilma can exist without the leaf reduction gene(At this point, my definition of micro dwarf is the characteristic immediate termination of 2 flower clusters on the main stem with no sympodial repeats of flowers and leaves.)

What we're after is the dominant genes if we were to trust all these studies. If I had to assume, however:
There should be a set or sets of genes that reduces overall height in a very major way. Even without the dwarf gene, Micro-tom with the non-dwarf D gene remains at around 14 inches tall. Only time will tell, and isolating two dominant traits is going to be an interesting challenge. I feel that I'm going to see a lot of tall plants with small 5 leaflet leaves in the future.

The only gene that seems co-dominant is Micro-Tom's early flowering gene. Based off of crossing studies, Micro-Tom produces flowers after growing only 5 leaves and F1 crosses with the determinate M82 variety has an intermediate phenotype of 6 leaves. However, that has mainly been bred out from many other Micro varieties(the micro varieties I'm growing flower at 8-9 leaves). Therefore, best case scenario, we are working with 3 genes: Dwarf(d), a leaf reduction gene, and another miniaturizing gene that may or may not be dominant.

[KaguyaCloud]

Update: 3/1/24
Images found here for progression: https://imgur.com/a/NOXvlYy
It has been 1 week since the JoRo F1 seedlings opened their cotyledons. The plants are 4cm tall from the soil level to the meristem(tip of the stem) and beginning to put out their third leaf, which may have 7 leaflets.

Growth rate is faster than I anticipated. It could be due to heterosis, putting the germinated seedling earlier into the potting mix, or the new growing media I have made. Overall it looks like it is growing like a typical indeterminate. Foliage is starting to smell citrusy like Jochalos.

I have also harvest seeds from my one Micro-Tina, as my original seed that I have ordered from Utah State University are pretty old. I have collected and am drying 63 seeds from 4 tiny fruits to save for future potential breeding projects. While Micro-Tina's flavor isn't all too impressive, it still has value due to it's high harvest index, earliest days to flowering, and a direct pedigree with Micro-Tom. And, to be honest, I have some level of sentimental value to it. It was the first thing I've ever grown indoors.

Also, I have found out that Jochalos and Orange hat have 6 sepals vs Vilma and Rosella having 5.

[KaguyaCloud]

Very interesting, so in 70 days you can breed a new generation.
Let say 7 days for germanation seeds, you don't have to ferment them. Allowing the seeds to dry with gel on a paper for an hour is sufficient before sowing them.
And then after germination another 63 days until harvesting the fruit.

Best case scenario, I can breed 5 generations in one year. However, due to not knowing the probabilities of getting the micro trait in a small growing space, I predict it's going to take me several months of selecting and jotting down phenotypes before I find the right F2. If I am committed enough, I can grow up to 20 individual seedlings at a time and select towards the micro phenotype in just 1-2 weeks.

[AKgardener]

So if I want a bigger tomato on a smaller plant I use the dwarf as the mother and larger one as the father?? Or the opposite

[KaguyaCloud]

So if I want a bigger tomato on a smaller plant I use the dwarf as the mother and larger one as the father?? Or the opposite

I'm assuming you have a small fruiting dwarf plant and a larger fruiting regular plant to start off with. If so, then it's best to use the dwarf as the mother and the father as the pollen donor. This is to indicate that the cross is successful. Let's start with plant size:

If the cross is successful, all the seeds from the dwarf mother will grow like the father plant since they would be heterozygous dominant for regular growth(Dd).

If the cross was not successful, then the next generation collected will only be dwarf because the flower self pollinated and there would be two copies of the dwarf gene(dd).

When you use the regular growing large fruited plant as the father, there's no way to immediately confirm that the cross is successful in the F1 generation. This is because a successful and unsuccessful cross would yield a regular growing plant, and you would only know if the cross is successful once the plant begins to bear fruit.

As for large vs small fruits, there are multiple genes that control the size of the fruits itself. However, from the many crosses done between cherry and beefsteaks, the smaller fruit size seems to be dominant. You would likely need to either plant a lot of F2 seeds and/or continuously back cross every generation with the larger fruiting father to get larger and larger fruits, while also needing to isolate the dwarf gene as well.

[AKgardener]

Whew okay thank you I was thinking of trying it down the road. Sounds like a lot of work but worth it if it turns out

[KaguyaCloud]

I encourage you to try it out either way. You don't really need to know too much on genetics beyond dominant and recessive traits. Start small and with a goal, then build off from it.

For example: I want a micro-dwarf that has the characteristics of a tasty tomato like Rosella Cherry. Therefore, I have made an F1 cross where Jochalos(micro) is the mother and Rosella Cherry is the father. I also want to publicly document crossing and selecting a Micro x Indeterminate so that other people can breed micros as well.

If you have any other questions, let me know. I'm quite new to this however, considering that I started breeding tomatoes 4 months ago when I started this thread. If I am ever successful at this, I will start a new thread in this forum with everything I have learned.

[wykvlvr]

wry grin you forgot the EXCEPT if one plant is rl and the other plant is a pl or has some over recessive foliage type. In that case if the cross is successful the seedlings will be regular leaf. This is why many of my crosses this year will be micro pollen to potato leaf or variegated leaf big plant.

[KaguyaCloud]

wry grin you forgot the EXCEPT if one plant is rl and the other plant is a pl or has some over recessive foliage type. In that case if the cross is successful the seedlings will be regular leaf. This is why many of my crosses this year will be micro pollen to potato leaf or variegated leaf big plant.

Oh if that’s the case, then crossing where the micro is the pollen donor is an easier option when the mother is a potato leaf. The flowers of micro tomatoes have the tendency to break when you emasculate them. Using a a potato leaf as the mother will also work just as well, if not better.

What potato leaf varieties do you plan on crossing?

[wykvlvr]

Yes
IF your micro dwarf has regular leaves (some I have don't) and the plant you want a cross from has PL, chartreuse, variegated, or fuzzy leaves then you can use the micro pollen to large flower. All the F1 from the cross will have regular leaves.
IF your micro dwarf has possible potato leaves then use the chartreuse, variegated or fuzzy for RL plants in the F1
IF your micro dwarf is regular leaf and so is the large plant you want to use then you need to go the other way to tell in seedlings. ie short are not crossed tall are.
And lastly you can use color as a way to tell if your cross is successful, however this requires you grow out your possible cross plants to fruiting stage. In this instance your micro should be red and the large plant should have almost anything but red tomatoes. Red tomatoes in seedlings would mean a successful cross.