Micro dwarf x Indeterminate cross ideas.

[KaguyaCloud]

Curious of what kind of grow lights you use?? I’ve been up and down with mine

I settled with relatively mid ranged Monios T8 2ft grow lights from Amazon that are about 24 watts per light(6 pack is $60-80 depending on sale). Any 2ft white LED bar lights that use about 24 watts per individual light will do, no need to use anything expensive. The lights effectively cover a 22 inch by 3 inch area if you plan on growing tomatoes. Space the lights 1-3 inches above the foliage of the plant for maximum amount of concentrated light. I also use a digital timer on the outlet that turns the lights on for 15 hours every single day.

[KaguyaCloud]

I think my first step is going to be acquire and grow out every compact dwarf variety I can get my hands on, and play around with stunting larger cultivars. I'll probably mirror your cultivation methods (which I see as something of a crossbreed that might already yield most of the benefits of hydro cultivation) but I'll also probably rig up a few simple systems to compare results. I've read about good results flavor wise by moving plants to 'soil' for fruiting, so that'll be something to explore as well.

Just out of curiosity what are your goals in breeding these tomatoes?

Stunting large varieties for me has been quite a bit of a challenge. 4 inch pots can grow really large tomato plants if you give them enough nutrients and light. It's possible that the best way to stunt them is the use 2 inch cells, but watering them may be a large hassle to do. My cultivation method is a standard soilless set up with consistent hydroponic fertilization as a technique. It's basically a modified Bruce Bugbee cultivation method with coconut coir and perlite as the planting media. You water the pot with nutrient solution until 10% leaches out, measure the nutrient levels with a regular ppm or EC meter, then water with tap or dilute hydroponic nutrients depending on the nutrient levels.

When growing in very small containers, there will never be enough nutrients in the media to support a growing and fruiting plant, which is why the hydroponic nutrients are there to feed them. If you would like, I can give you extreme details on exactly what I have done and have bought.

[AKgardener]

@KaguyaCloud thank you I grow pretty much all micro during the winter so I’m always looking for what others use ..

[Lisaliza]

Just out of curiosity what are your goals in breeding these tomatoes?

Boy, I wish I could answer that with any measure of confidence! The most honest answer is that I'm doing this to move on from my new obsession - my hands are tied, I have to run with it until I achieve some level of mastery or become bored. The latter is, of course, more likely.

I'm sure that's not the kind of goal you were looking for, though! I don't have a particular plant/fruit combo in mind at all, my goal is much more nebulous. It boils down to an interest in optimizing home/local food production - maximum (supermarket quality or better) yield for minimum inputs. In my mind, time spent on labor is the most expensive of all inputs, followed by space (indoors, volume) and elapsed time. At this stage, I'm taking that to mean high yielding compact plants whose needs can be mostly automated, with as much resistance / tolerance / nonspecific diversity as I can manage to cram in. Past that, I have no idea where I'm heading. I'm very intrigued by concepts like landrace gardening and promiscuity, and I have some fuzzy vision of developing my own 'master parent' lines for amateur use. In the end, I'll likely settle for just having learned something new - but you never know, maybe I've finally found the thing that stays interesting forever.


Re: stunting, I'm really only interested in it as a means to an end - the 'wild' types whose genes I'm interested in tend to be massive, and it would just be nice if I could keep the whole project at home in the no-pants zone.

If you would like, I can give you extreme details on exactly what I have done and have bought.

I will almost definitely take you up on that when I've moved on from the seedstock portion of the buying spree! There are so many components I have yet to even consider. Many of the cultivars I'm particularly interested in don't appear to be available in the US, so I have to get those orders placed and start the clock on that.

[KaguyaCloud]

Update 8/28/24:


The right Joro F2 plant has begun to ripen. Lots of fruit has started growing. It has been 53 active growing days since the initial planting(55 days minus 2 days without power).

Left F2: Exhibits indeterminate growth habit. Heavy fruit set. I've noticed that the amount of pollen that the flowers of this plant is significantly more than the right F2, which is likely attributed to the Micro parent Jochalos. I've noticed that the smallest micro dwarfs exhibit much more pollen shedding when shaking the flowers compared to the indeterminate cherries I have been growing.

Right F2: Exhibits micro-like growth habit. Despite having many more flowers, it seems that the right F2 has lower fruit set. However, it looks like it is setting fruit in layers at a time like the indeterminate parent Rosella Cherry. The flowers that have yet to develop fruit have very stiff joints, which should be an indication of some-what successful pollination. In addition, it apparently has the uneven ripening gene pattern from Rosella Cherry. Rosella Cherry's fruit set has green shoulders at around the base of the sepal region, but does not spread out further more than that. The leaves do not seem to exhibit the leaflet reduction gene, as some grew to be extremely large compared to the micro parent.

Overall, this is pretty exciting to see. It looks like my growing conditions make it so that 55 days is the average from open cotyledons to the breaker stage of the fruit. I expect another 7 days for the fruit to turn color and then another 2-3 weeks for the fruits to fully ripen on the vine. If I am impatient, I could pick the fruits once it has turned its final color, but what would be the point of doing that when I'm selecting for flavor?

Assuming maximum amount of sweetness and flavor of the fruit itself, the timeline of a full generation is as follows:
Germination to open cotyledons: 7 days
Open cotyledons to first flower: 27 days
First flower to first blush: 28 days
First blush to final color: 10 days
Final color to full ripening: 14-21 days
Seed collecting, drying, freezing: 7 days.

Maximum range per generation: 93-100 days.

At a leisurely pace, I can breed a generation every 100 days, which would be 3.7 generations per year. However, if the flavor is well preserved, I could start seed collecting at final color instead of full ripening. This would shorten it down to 79 days or 4.6 generations per year. I wonder how many generations would it take for good flavor to be well established.

[bower]

I love the loaded truss on the plant on the left!
Interesting it appears shorter than the other, even if it is an indeterminate pattern.
Both are certainly compact enough to be well suited to the indoor environment, and still producing fruit quite early.

[Doffer]

I think u can collect seeds at blush stage. This will shorten to 69 days.
When u do the tatse test at full ripening u only ceep the seedslings from the best plant. And give them a bigher pot.

[KaguyaCloud]

Mapping fruit color traits:

Based off the ripening behavior of the rightmost Joro F2, it seems to have a very pale yellow color. It's possible that it may be yellow/white tomato. I wonder what are the possible homozygous genetic combinations and colors that could arise from these sets of genes. Here are the potential genotypes of the fruit traits:

Rosella: Clear skin(yy), red flesh(RR), green flesh(gg), uneven ripening(UU). This leads to a dark burgundy colored tomato with green shoulders.

Jochalos: Yellow skin(YY), low lycopene flesh(rr), no green flesh(GG), uniform ripening(uu). This leads to a yellow colored tomato. Although, the skins do eventually turn orange.

Joro F1: Yellow skin(Yy), red flesh(Rr), no green flesh(Gg), uneven ripening(Uu). This leads to a red colored tomato with green shoulders.

Potential colors of the F2(Skin ; Flesh color 1; Flesh color 2):
YY, RR, GG: Typical red tomato (yellow skin + red flesh)
YY, RR, gg: Brown tomato (yellow skin + red flesh + green flesh)
YY, rr, GG: Yellow/Orange tomato(yellow skin + yellow flesh)
YY, rr, gg: Yellow-green tomato(yellow skin + yellow flesh + green flesh)
yy, RR, GG: Pink tomato (clear skin + red flesh)
yy, RR, gg: Burgundy red tomato(clear skin + red flesh + green flesh)
yy, rr, GG: White/Pale yellow tomato(clear skin + yellow flesh)
yy, rr, gg: Pale yellow-green tomato(clear skin + yellow flesh + green flesh)

Well, that's quite a few color combinations for sure. I had zero intention of having such a large spectrum to work with.

[Doffer]

Ad the Uu genes and u have even more combinations.

[bower]

Ad the Uu genes and u have even more combinations.

What happens with them @Doffer ? I've noticed that some F2's have varying amounts of green shoulder, although not sure if uu was in the parentage. Are there QTL's involved in green shoulder expression?

[KaguyaCloud]

I assume that it means there are even more phenotypes, so that list would be twice as large with each half getting either uniform ripening or green shoulders.

I've noticed that some F2's have varying amounts of green shoulder, although not sure if uu was in the parentage. Are there QTL's involved in green shoulder expression?

Based off of my personal experience, it seems that there definitely is something affecting the levels of green shoulders in the F1 and F2. And whatever it may be, it seems recessive. Rosella Cherry has the green shoulder genes, but it seems very suppressed and only covers just the top 1/8th of the tomato.

The F1 has green shoulders that covers up to 1/3 of the fruit. However, the smaller shoulders came back in the F2. Because the one parent has the uniform ripening gene and that larger shoulders are dominant in the F1, it's guaranteed that there seems to be some recessive gene that represses green shoulders coming from Rosella.

We could eliminate several potential chromosomes since certain recessive traits from the micro parent have replaced the indeterminate parent: dwarf gene, yellow flesh, determinate(?).

All I can really do is hypothesize things such as a spherical fruit shape and long sepals as potential links, but those could be coincidences from the gene shuffle in the F2.

[KaguyaCloud]

Update 9/3/24:
It seems that the Joro F2 Right fruit has fully ripened, as it is very soft to the touch despite the ghostly yellow color. Joro F2 left is beginning to ripen.


Unfortunately, there were zero seeds in the first fruit despite being the largest fruit on the plant. Crossing my fingers to at least get one seed from this line. I did notice that the flowers on the right F2 did not shed much, if not any pollen at all. Early flowers also exhibit exerted styles. It likely obtained this nearly seedless trait from the indeterminate parent, Rosella Cherry. Is this parthenocarpy?

Fruit structure is very meaty, exactly as meaty as Rosella Cherry in fact. Skin color is very clear, meaning it does have the clear skin gene, like in Rosella Cherry. The gel inside is a clear color.

While there's is flavor from the right F2 reminiscent of Rosella, the intensity of the flavor is very diluted. There's also no sweetness or sourness to the fruit either, making it quite watery. I may need to wait longer, however I feel that it might become very mushy by then.

If the next fruit does not have any flavor to it at all, I will likely save a few seeds and note it down as a dead end in terms of flavor genetics, which is a shame considering that it has the early termination gene. On the upside, it seems that flavor seems to segregate independently from fruit shape, fruit internal structure, and leaf shape.

Now that I know that I could potentially have bland tomatoes despite all those Rosella phenotypes being expressed, I might get aggressive in the culling on my next F2 growing trials or hoping on the left F2 to have some flavorful genes in it.

[bower]

Taste certainly does segregate independently from other fruit traits - 'taste' is such a complex trait that many QTLs are involved. If the parents are divergent at all in taste qualities, you can continue to get different tasting tomatoes right to F7. So don't write off the line at this stage where you've only selected for growth habit. If you don't get good taste in the next generation, you would probably be best to focus on other lines.
Last season I had a F3 GWR bicolor that was selected for determinate growth habit. The taste was not exceptional, but I grew two plants this season anyway for some disease resistance comparisons. Shockingly both of these plants have outstanding fruit taste this season, and top rated even compared to my favorites. Possibly the taste genetics was there but simply wasn't well expressed due to less optimal growing conditions last year. Or it could be that I just lucked out, and picked two seeds that had a higher Brix combination of alleles, and that brought out the taste complexity. So although it's generally not advised to select away from taste, I'd give it a second generation to express that, or at least save some seeds for a rainy day to check it out. You may also find that later fruit taste different, although IDK since your conditions are so controlled, how much variation there might be on the plant.
The ability to set without pollinated seeds is parthenocarpy, indeed. It's more common than advertised, at least, you can find plants in the general body of OP's/heirlooms that will do that in some conditions, although more commonly the unseeded fruit are smaller than normal, and not larger. It would be unusual to have all unseeded fruit on a plant though.

[KaguyaCloud]

The parents are indeed very divergent in flavor. I crossed a fruity, sweet, and low acid indeterminate with a neutral flavor, slightly acidic micro. In terms of growing conditions, the two F1 plants that I originally grew tasted exactly the same while being grown in the same set up, so there shouldn't be too much variation in flavor and sweetness at the very least. However, I am going to wait to see if any additional sweetness pops up the longer it is attached on the vine before making anything conclusive. If it turns out to still be not great, I will save seeds and continue to start growing the other 2000 F2 seeds that I have collected. There's so much potential for flavor if I can start over.

[KaguyaCloud]

Update 9/21/24


Tomatoes have fully ripened on the vine. Both F2s have very thick walls and meaty interiors, which is something that is quite nice.

Left Joro F2: Maintains indeterminate growth habit with leaf reduction gene. It has yellow skin, red flesh, and is heterozygous for green gel. Flavor-wise, nothing impressive, but it is very sweet like the F1 parent.

Right Joro F2: Still maintains the shoot architecture of a micro dwarf, but with longer internodes and larger leaves. It has clear skin, yellow flesh, and green gel. Flesh is very soft when ripe, practically like the consistency of a grape. It has the intense flavor/aroma of Rosella Cherry, a very tiny amount of sweetness, and has zero sourness. The flowers seems to exhibit extremely low fertility, as the vast majority of the fruits are seedless.

Overall, very interesting that I got all the sweetness from one and all the aroma in the other, but I think backcrossing the pale F2 with the original parent Rosella Cherry might be the best way to maximize flavor. As the Right Joro F2 has the flavor I am aiming for. I have already begun to save seeds for both varieties. I think another 200-300 seeds per plant should be sufficient to maintain diversity.

I'm glad I'm making some progress, but I think the plan now is to grow out a few of the pale F2 generation to see if any additional sweetness genes might come back. The color would likely be preserved due to the recessive nature of the flesh color genes. That being said, I also plan on backcrossing the pale F2 with Rosella to add additional flavor genes, making it hopefully 75% Rosella Cherry in terms of fruiting quality.

[bower]

Have you considered a cross between the two micro F2's? That would combine the aroma genes with those for sweetness, without having to re-select for the growth habit.
Not that there's anything wrong with your plan, either. If you want to maximize resemblance to RC fruit quality, the parent backcross is the way to go.
Flavor is so complex, sometimes it seems to be fixed early, with few outliers, and in other lines keeps varying every generation.
Sweetness is an additive trait, which means it is pretty easy to retain once you find it. Or so it seems to me. Your sweet fruit has a good combination of quantitative alleles that add up, so they should produce some sweet descendants in the next generation.

[KaguyaCloud]

Have you considered a cross between the two micro F2's? That would combine the aroma genes with those for sweetness, without having to re-select for the growth habit.

I did consider performing a cross between the two, however I am worried about the flavor/micro genes that may be lost in the subsequent generations. While both of the micros do grow very small, the genes involved are quite different and may cancel out the micro traits due to how recessive each of those micro traits are after observing the F1 growth habit. The major two genes that cause micro dwarf growth habit when combined with the dwarf gene would be the leaf reduction(reduced leaves and extremely short internodes) and early stem termination(early stem termination with two flower clusters).

Sweet F2 has: Dwarf(d/d), Indeterminate growth(Sp/Sp or Sp/sp), Leaf reduction(lr/lr), no early stem termination(Es/Es or Es/es)
Aromatic F2 has: Dwarf(d/d), determinate?(sp/sp), no leaf reduction(Lr/Lr or Lr/lr), early stem termination(es/es)

A cross may have a high likelihood of producing a dwarf(d/d) indeterminate(Sp/sp)with no leaf reduction(Lr/lr) and no early stem termination(Es/es). Statistically it is less likely, but there's also a chance the flavor genes are going to be reshuffled again due to one not being sweet and the other not being aromatic.

There seems to be a reason why many micro breeders have a lot of trouble maintaining good flavor, and it may be due to particular micro genes. And while I say the Sweet F2 is very sweet, that sweetness is not really consistent. It's possible that the leaf reduction gene might be involved in causing reduced/inconsistent flavor, so I'm very hesitant to perform an F2 cross.

All that I know is that sweetness can be preserved with dwarf + leaf reduction and that strong aroma can be preserved with dwarf + early stem termination. Whether or not that could be done with dwarf + leaf reduction + early stem termination requires more experimentation and crossing. But knowing how flavorless a lot of the pure micros I have grown are, it seems risky to explore that. Since I am prioritizing flavor over everything, it is more favorable for me to perform a backcross and reselect for growth habit.

[bower]

Wow - very cool and interesting issues with flavor linkage and micro - I didn't know about that.
It's often difficult to tease out the traits that have environmental variation as well - I do put variation from fruit to fruit on a plant entirely to the cause of environment. Some plants are more consistent than others, it's true, but the cause must be environmental - even if the difference is number of inches from your light source in a heavily controlled environment. Minor difference in degree of ripeness is another cause which is basically environment as well (considering time on the bush as a dimension of the environment).

[KaguyaCloud]

Environmental cues definitely affect flavor by a large amount. For some reason, the tomatoes that I grow indoors do not turn sweet or flavorful when they turn their full color. In fact, it takes 2-3 weeks after turning color on the vine to develop good flavor. Not sure if that's normal or not, but I am also working with cherry/micro tomatoes, which might ripen differently from larger varieties.

I did make an attempt to grow the F1s outside in my patio that gets 3 hours of direct sun per day. They fruited but were always bland no matter how long they stayed on the vine.

I do know that the original tasty parent Rosella Cherry stays very consistent in flavor regardless of variable growing environments and that the pale aromatic tomato has conserved this consistent flavor characteristic. Although, it is really difficult to determine how ripe the fruit is due to the very translucent nature of the fruit.

[bower]

Flavor consistency across conditions is an important trait alright.
I always try to get someone else to taste the tomatoes that stood out for flavor. One problem is having an optimally ripe fruit when the opportunity arises for a taste test. Some fruit are at their peak when very ripe, but others also change taste as they become overripe, and are better eaten early. I was disappointed a couple of times this season, when the fruit was riper or not as ripe as when I first tasted and thought it was special.

I rarely see full ripeness and flavor from fruit that have just reached full color. I can usually tell after I picked, at least, that in spite of the look of readiness they're still overly firm and not as deeply colored as they appeared to be. So my fruit go to sit in a triage area - a cool room (relatively) that ranges from mid sixties to low 70's, where they can slowly reach prime condition. Hotter or cooler than that, is not optimal for flavor development, and might be a factor with your patio tomatoes.