Micro dwarf x Indeterminate cross ideas.

[wykvlvr]

The fact of the matter is I LIKE potato leaf for my area. They grow well here, they protect the tomatoes from sun scald and just seem to be more resistant to our climate so I tend to select PL varieties if one will work for the type of tomato I want to grow so I do have a few PL dwarfs on the list but not sure which ones I will attempt to use for crosses. Most are new to me varieties so I want to see if they have the flavor I want to bring in before deciding which to use.

The truth is I am still sorting out what I want to grow this year as I have 2 to 3 week before I will start my tomato seedlings. AND I recently stumbled onto some "varieties" that have been selected to grow in a climate similar to mine that I now want to grow so I have to balance new interesting vs known producers and of course possible tomatoes for crossing to my micro dwarfs... Wry grin ask me again what I will be using in about 3 to 4 weeks when I know what i planted and what actually sprouted.

[KaguyaCloud]

Update: 3/4/24
It seems that the leaf pattern of both of the the JoRo F1 is a 3, 5, 5 leaf pattern, which is a similar leaf pattern to Vilma. I am germinating 2 rosella seedlings as a base reference again just to make sure I did not miscount the number of primary leaflets on Rosella.


I have made a diagram of what I've observed in Micro Dwarf leaf, shoot, and flowering architecture in the main stem. The axillary shoots are more variable and difficult to determine. These are very general diagrams, so let me know if there are any errors that can be found. The two slashes in the middle of the stem indicates skipping a number of leaves until we reach the region where there are flower trusses.


Due note that the number of leaflets grown is dependent on how much light the seedlings are growing, and this chart is based on growing the plants at 40,000 lux or greater at the top of the canopy for 15 hours.

[bower]

That is a great template for shoot architecture, very nice!
I agree that environment may vary leaflet number as much as heredity, but if you can use it to advantage in a controlled environment, that's great.
I'll be curious to learn whether there is as much variation in microdwarf leaf/flower patterns as there is in determinates, and the plasticity they seem to pick up from being crossed to indeterminates.

[KaguyaCloud]

Update: 3/5/24

Well, interesting stuff has happened again, as the JoRo F1 has grown another leaf. The leaflet pattern now is 3, 5, 5, 5. Every additional leaf shows increasing amounts of secondary leaflet growth. Now this is just downright strange. On one hand, it's good news that the leaf reduction gene can be selected early on, as those that are homozygous with the reduction gene will have a 1/3/5 leaflet pattern. We can differentiate between heterozygous, homozygous normal, and homozygous reduced leaves.

On the other hand, this trait is not recessive at all, but causes incomplete dominance. This means that the trait is intermediate between the two parents(red flower x white flower = pink flower for example).
2 parents exhibit:
1, 3, 3, 5, 5(17 leaflets)
3, 5, 7, 7, 7(29 leaflets)

F1 exhibits:
3, 5, 5, 5, 5?(23 leaflets?)

Average between 2 parents:
2, 4, 5, 6, 6(23 leaflets)

So this trait is approximately intermediate when heterozygous. I suspect that eventually the F1 will grow 7 leaflet leaves at a certain point due to the fact that the micro dwarf varieties tend to do so after their 5th leaf growth. Due to Vilma existing and having a 3, 5, 5, 7, 7 leaflet pattern, I think I'll hypothesize this:

There may be 2 genes involving leaf reduction, both being some-what incompletely dominant:
1. Being heterozygous for both creates a 3,5,5,5,5? leaflet pattern.
2. Being homozygous to one of them creates the 3/5/7 leaflet phenotype(Like in Vilma).
3. Being homozygous to both leaf reduction genes creates the 1/3/5 phenotype(Like in Jochalos, Orange Hat, and Micro-Tina).

This is a double edged sword. What exactly would happen if an F2 was homozygous for one leaf reduction gene but heterozygous for another leaf reduction gene? The idea of having even more variable leaflet patterns is probably going to cause some headache during F2 selection. I'm glad that the leaflet patterns of the smaller micro dwarf tomatoes I'm growing are at least consistent in pattern.

Good news is that if there are 2 genes for leaf reduction, then all that is left is finding the gene that causes early termination of the main stem and/or shortened internodes. Although, I assume that early termination of the main stem is going to work in conjunction with the sp gene(reminder that the early termination gene also has incomplete dominance since crosses of micros with determinates yielded intermediate flowering patterns as well). But we shall see.

[maf]

I wouldn't rule out dwarf (d) from having an effect on patterns of leaflet numbers. From TGRC

leaves very distinct, with reduced number and size of segments; dark green color, puckered rugose surface, down-curled magins, and broader, shorter outline of whole as well as individual segments

While I know segments does not equal leaflets exactly, it has always seemed to me that the number of leaflets on dwarf plants I have grown was reduced compared to wild type. Admittedly I haven't done a proper leaflet count to back this up... just putting the idea out there for discussion...

[KaguyaCloud]

While I know segments does not equal leaflets exactly, it has always seemed to me that the number of leaflets on dwarf plants I have grown was reduced compared to wild type. Admittedly I haven't done a proper leaflet count to back this up... just putting the idea out there for discussion...

That is very true. However, I was under the assumption that the dwarf gene was recessive and wouldn’t show much difference in heterozygous F1 plants. Or is it just rugose leaves that it doesn’t express? In all the posts I’ve read so far, it seems that indeterminate x dwarf just produces another indeterminate phenotype.

[maf]

While I know segments does not equal leaflets exactly, it has always seemed to me that the number of leaflets on dwarf plants I have grown was reduced compared to wild type. Admittedly I haven't done a proper leaflet count to back this up... just putting the idea out there for discussion...

That is very true. However, I was under the assumption that the dwarf gene was recessive and wouldn’t show much difference in heterozygous F1 plants. Or is it just rugose leaves that it doesn’t express? In all the posts I’ve read so far, it seems that indeterminate x dwarf just produces another indeterminate phenotype.

Yes, sorry didn't realise you were only talking about dominant traits that would express in heterozygous condition. Of course d is recessive and it is very difficult to identify heterozygotes.

I've seen a couple of mentions in this thread of dwarf (d) not affecting leaflet numbers and thought you were talking more in general... ie. you were ruling out d as a source gene for decreased leaflet numbers in your breeding population in general... quotes such as this from Feb 29th:

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.

[KaguyaCloud]

I've seen a couple of mentions in this thread of dwarf (d) not affecting leaflet numbers and thought you were talking more in general... ie. you were ruling out d as a source gene for decreased leaflet numbers in your breeding population in general... quotes such as this from Feb 29th

Ah sorry about that. I wasn't fully clear on what I meant. In that case I meant to say that the dwarf gene alone doesn't fully reduce the leaflets on the tomato seedlings down to a 1/3/5 leaflet pattern, as the micro-dwarf Vilma and potentially other dwarfs do have larger and less reduced leaves. I'm assuming it's likely there's another gene that is causing the full reduction of the leaflets, if that makes sense.

[KaguyaCloud]

Update: 3/7/24
It has been 13 days since the JoRo F1 hybrid has grown and we already have flower buds. This is a lot faster than anticipated, as it was 17 days for my Jochalos Micros to start showing signs of visible flower buds compared to Rosella Cherry started showing flower buds at 19 days. There are too many variables to determine right now if early flowering is caused by better growing conditions or genetics(such as hybrid vigor). That being said, I'm still curious to see what the flower and leaf patterns will be.


The main stem height also seems to be greatly reduced. Currently the JoRo F1 is only 9cm tall and already showing flower buds. Meanwhile Jochalos started showing flower buds at 7.5cm and Rosella Cherry started showing flower buds when it was 25cm tall. This extreme reduction might indicate that there may be a very dominant or incompletely dominant gene responsible for reducing internode length. At this point, I am convinced that internode reduction might be due to a gene that is not recessive at all considering the large height difference between the tall parent and the F1. This may explain the inconsistency of attempting to breed micro varieties, as a dominant or incompletely dominant genes mean potentially tall individuals popping up in future generations.

[bower]

13 days... I'm speechless. Truly awesome.

[KaguyaCloud]

13 days... I'm speechless. Truly awesome.

Honestly, I have no idea what's going on. The lights are the same. The temperature is still consistent. The only difference is the soil mix I made and the genetics. But reducing the potential generation time by another 5-7 days is a major leap regardless. It seems like everyday I'm learning something new from these F1's and it's quite exciting.

[maf]

Out of interest how many hours of light and what are your day high temps and night lows in the grow area?

[KaguyaCloud]

Out of interest how many hours of light and what are your day high temps and night lows in the grow area?

I am providing approximately 40,000lux of light at the top of the canopy for 15 hours a day. Daily high and low temps are around 76-85F since it's indoors. Intensity of light matters just as much, if not more than duration. For example, here are some strawberry plants that germinated at the same time with the same number of hours of light, but at different intensities. The leftmost plants were grown at half the intensity as the one on the right:

[maf]

Thanks, 15 hours a day is about what I usually use, and good to know your temps too.

I understand about light intensity and growth. A bit overkill for young tomato plants, but I had good success with a 400 watt metal halide lamp before!

I don't know if you had considered this, but root space also has an impact on time to flowering - the larger the pot, the bigger the plant will grow (and the longer it will take) before initiating flowering.

[Doffer]

13 days, unbelievable.
My seedlings were sown on 16-02, germinated on 21-02 and now have 5 real leaves and are about 8cm high.
they get 40,000+ lux for 16 hours and the temperature is 25 to 30C. However, I don't see any flower buds yet.
They are in small round pots of 3 x 3 x 3 cm.

[bower]

Another factor for early flowering is phosphorus levels. Generous phosphorus in a small pot promotes early flowering as the plant reaches the limit for root growth but still has excess P available for flowering. Commonly used to grow bulbs indoors aka "forcing".

I think it's not too unusual to see F1 or F2 outstrip the earliness of either parent by several days, or as much as a week. Environmental conditions as well as parent genetics seem to play a part in pushing the limits (transgressive segregation). In my breeding work exposure to cold seems to tell the plants to 'hurry up' for a short season.
So in this case, the effects of high lumens and high temperatures seems to be pushing faster maturity as well...

Did you know @KaguyaCloud the conventional wisdom is that tomatoes will not set fruit if night temperatures are above 70F. This didn't seem to be a problem with your earlier generation, but I thought I would mention it, in case you have difficulty getting them to set with a night of 76F.

[KaguyaCloud]

My seedlings were sown on 16-02, germinated on 21-02 and now have 5 real leaves and are about 8cm high.
they get 40,000+ lux for 16 hours and the temperature is 25 to 30C. However, I don't see any flower buds yet.
They are in small round pots of 3 x 3 x 3 cm.

I think you're making good progress! They're about as tall as my seedlings, which are currently growing out their 7th true leaf. It could be a nutrition issue since your pots are so small. I am currently using a 4 inch (10cm) diameter pot and monitored the ppm of the leachate to around 700-1000ppm. The soil mix I used is fertilized with a low diluted hydroponic fertilizer, which is the same concentration I use at every stage of development. I do water with non-fertilized solution(just filtered water), but the plants can reach a point where they usually can continuously drink the diluted fertilized solution as long as I collect the leachate.

Another factor for early flowering is phosphorus levels. Generous phosphorus in a small pot promotes early flowering as the plant reaches the limit for root growth but still has excess P available for flowering. Commonly used to grow bulbs indoors aka "forcing".

Did you know @KaguyaCloud the conventional wisdom is that tomatoes will not set fruit if night temperatures are above 70F. This didn't seem to be a problem with your earlier generation, but I thought I would mention it, in case you have difficulty getting them to set with a night of 76F.

Huh, that's very interesting considering that phosphorus is actually the lowest concentrated macro nutrient in my fertilizer(MaxiGro 10-5-14). And I did not know that the conventional wisdom was that. I've mainly noticed failed fruit set or flowers dropping when the soil is too dry or if there's not enough nutrient solution inputted into the system.

Currently I have a 4ft long Rosella Cherry tomato that's still growing in a 4 inch pot and is still setting fruit, so it's possible to continuously have a plant grow even in a constrained space. There was a period of flower drop due to COVID, but it's recovering again now that I can care for it.

[KaguyaCloud]

Update: 3/8/24
Joro F1 hybrid seems to be pretty healthy. I wonder if more tomatoes per truss is a dominant or a recessive trait, as Rosella Cherry usually branches and has the tendency to produce around 13 flowers in it's first truss.
Progression Picture Update:

[KaguyaCloud]

Update: 3/15/24

Confirmed that the flowers have began to open in my JoRo F1. This would make it 21 days to flowering from opened cotyledons for the hybrid cross. Plants are now 23 cm tall, which is about the same height as their parent Rosella Cherry. I accidentally snapped the flowering tip off the left plant in an attempt to bend it horizontally. Hopefully it recovers. With so many axillary shoots growing, I could just propagate another cutting in case of emergencies. If the growing tip doesn't survive, I could study the effects of side shoot growth of the axillary buds to see if there's any difference.

In addition, I would like to revise my previous statement on leaflet number as the leaves begin to fully mature. It is now this:
3, 5, 5, 7, 7.

In terms of leaflet number, it seems to follow the pattern similar to Vilma, a variety with unreduced leaf but early main stem termination. This is promising, as it seems that the leaf reducing gene is mostly recessive.

Also some other noticeable observations:
-Smaller number of leaves to flower is...strange. F1 grew 7 leaves before putting out a flower truss. Jochalos grew 9 leaves and Rosella Cherry grew 8 leaves before producing a flower truss.
-F1 flowering pattern seems to look normal to a regular flowering pattern for indeterminates, where there is 3 leaves for every flower truss that grows.
-Creating a heavy number axillary shoots seems to be dominant
-10+ flower trusses in Rosella Cherry is dominant over 5-8 flower trusses in Jochalos.

[maf]

Update: 3/15/24

-Smaller number of leaves to flower is...strange. F1 grew 7 leaves before putting out a flower truss. Jochalos grew 9 leaves and Rosella Cherry grew 8 leaves before producing a flower truss.

I wouldn't read too much into this metric as environmental factors have a heavy influence on when flowering is initiated. For example: When the F1 was grown temps may have been more in the Goldilocks zone for flowering initiation. Or hybrid heterosis caused the F1 to use up the root space in the small container at an earlier stage and thus divert energy from root production to flowering sooner. Actually this last idea makes sense in that Jochalos being a smaller plant in all parts would take the longest to fill up the root space, and thus make the most leaves before flowering.