Micro dwarf x Indeterminate cross ideas.

[KaguyaCloud]

Update: 3/19/25


Joro F3-2 BC1 has finally germinated. The root size is as long as the indeterminate Rosella parent plant, which may be an indicator that the backcross is successful. I will check to see if there is any nyctinasty to confirm if it is the case once I plant it tomorrow. Statistically speaking, this generation should be 50% homozygous for Rosella and 50% heterozygous for both parents. This is much different from the F3 parent micro it descended from, which only was 37.5% homozygous for Rosella, 37.5% homozygous for Jochalos, and 25% heterozygous for both parents.

[KaguyaCloud]

Update 4/1/25 Joro BC1:


It's been about 12 days since I planted Joro BC1. However, I am unsure whether to update because this seedling expressed no nyctinasty after planting. It also isn't as large as the original F1 cross either despite the fact that it should have more genetics from the large indeterminate parent. So far, this plant has not displayed split branching from the either, and the leaves seem slightly rugose. I need to grow it further to see if the cross failed yet again. Luckily I crossed 2 fruits a few weeks back, so I have more insurance in case this one does not go well.

For the F2 segregation project, I found something interesting things. All the indeterminate F2s that I have grown, including the non-dwarf indeterminate, have axillary shoots that flower after 4 leaves have grown.

In another news, I have encountered an early tomato variety called "Scotia" in a discussion server. It's a normal leaf, super early determinate that is grown in Canada. And the flowering habit seems very similar to micro-dwarfs. It seems to grow 8-9 leaves before terminating immediately to 2 flower trusses.
https://www.tomatofifou.com/en/produit/scotia/

[bower]

IDK if Scotia is any earlier than the usual early red tomatoes. My friend has grown this one from time to time on her farm. They are vigorous bushes with fruit about the size of apples. About 3 ft tall under field conditions.

[KaguyaCloud]

Update 4/11/25:

Bad news. Cross failed again. This individual now known as Joro F4 has the early termination trait. However, I am currently germinating more attempted backcrosses that I have done about a month ago. Some interesting things did pop up, however.

Joro F4 does not exhibit split branching at the cotyledons, which might suggest that the trait is somewhat unstable. The leaflet pattern is 1-3-3-5-5-5.
Joro F4 grows 7 leaves before terminating to 2 flower buds just like the parent plant. The plant only has a 3 inch(7.6cm) long stem and is 4 inches(10.2cm) tall including the inflorescence. The main stem is extremely thick for a micro dwarf, it is as thick as a pencil, as shown in image 4 of the album.

[bower]

Too bad about the backcross fail, but at least there's something to be learned about the genetics/gene expression in every generation.
My hat's off to anyone who can handle those tiny flowers for crosses. Better luck next time!

[KaguyaCloud]

Update 4/19/25
F4 is growing nicely. For a compact sized plant, the flower trusses sure aren't. The plant is 3.5 inches at the internodes and the flower truss are around 3 inches tall. Such a strange, but fun size difference. It flowered 4/14/25, making it 26 days to first flower which is about average given my conditions.


F2 trials grew successfully. It was a pretty good idea to keep the F2s, as they show just how variable the dwarfing factors are despite all the individuals being indeterminate. I managed to harvest and taste some fruits from these individuals.


Joro F2 seedling 16: Non-dwarf, indeterminate. Grew extremely tall. 46 inches. Flavor is similar to the F1 parent. Sweet and okay tomato flavor.

Joro F2 seedling 7: Dwarf, indeterminate. Grew to about 22 inches. Flavor is faintly citrusy and sweet near the skin. Mainly bland however and has an off tap water after-taste. It's quite funny that this seedling grew about the same rate as seedling 12 before exploding in growth. This could be an indicator of putative mnt being only partially dominant early on.

Joro F2 seedling 12: Dwarf, indeterminate, more compact. Grew to only 8 inches tall. There is definitely another dwarfing factor that has not been characterized, likely has the putative mnt gene as it is a third of the size of Joro F2 seedling 7. The fruit flavor is excellent. Very sweet and richer in tomato flavor than the F1 parent. The tastiest individual of the F2s by far. It's rather unfortunate that it isn't determinate, but this individual is worth saving seeds for. It doesn't hurt to develop a line of flavorful micro indeterminates in the future.

Overall I'm quite happy with the F2 trials, it also shows that root size isn't really a good indicator of plant size, as seedling 16 has the smallest roots but is the tallest individual. In addition, all my current micros that I have selected for have long roots like the parent Rosella.

[bower]

Stoked to hear that you have a compact plant with excellent taste in the F2. You could have determinates further down the line, easily.

Images didn't load for me, btw. I'll check later and try again.

[Doffer]

Joro F2 seedling 12 could be heterozygous for Determineted.