The Tropical Fruit Forum

On the other hand weak roots are sometimes correlated with less thorns or precocious flowering. Just in case this is of interest.

I can not say. The seeds were given to me.

I think this phenomenon fits very well with the node count theory. Your trees have grown very fast and have reached the crucial height, that's why they are flowering .
From the reverse I can report that Poncirus hybrids here in northern Germany lack summer warmth and grow very slowly, mature poorly and often freeze back and stay immature for a long time.
Your trees have a long growing season a warm climate in the greenhouse and probably a good supply of nutrients. That speeds things up.
Ichangensis hybrids often start flowering on the lower branches first, interestingly ichangensis hybrids flower much faster and at lower heights than poncirush hybrids here even outside. In the greenhouse I had the first fruits in the 3rd summer at just about 1m height and that on the lower branches.
I think fast growth is very important, the genetic predispositions also play an important role and with fast growth these are fulfilled faster.

 Do you have any news on this topic?
Finally a received a Rose Anne. It started to flower around Christmas but lost it due to cold weather. I am eager to see if it will flower a second time in spring as promised.

Did you find it?

11 months from germination and it flowers? that is faster than I had hoped.

There are several varieties of citrumelo. They differ in taste, hardiness and so on. By and large, the rootstock is not very important for the taste. On closer look, there are some differences, but with citrumelos it's mostly a matter of whether they're edible at all....and this also depends on individual preferencies

P.polyandra is way less hardy than trifoliata. I would say -6°C is already a thread. I lost larger branches at -6°C.
It doesn't die at single-digit subzero temperatures, but it doesn't thrive either. I don't think it will survive -10°C.

I see potential in Meiwa Kumquat. It is sweet and maybe hybrids are more likely to be sweet then too... but I am only guessing. How is Nameiwa?
If you have the chance  it would be good to pollinate in both directions. Most of the time there are other restrictions, so if you have the chance to do so, do as much as you can and as many combinations as you can
There are always incompatibilities nucellar seeds and so on what can cross your plans.
Most of my plans remained plans because the plants decided otherwise.

IVIA-450    Poncirus Monoembriónico at IVIA and Monoembryonic trifoliate at UC Riverside are at least not polyembryonic thus probably zygotic.

https://ivia.gva.es/va/busqueda-por-orden-alfabetico-nombres-comunes

https://citrusvariety.ucr.edu/crc3888


@Ilya How do you distinguish zygotic from nucellar seedlings in Poncirus, aside from obvious polyembryonic seedlings?

Ilya, is your Kabosu hardy in your garden?

funny you! 

I was just looking for the parentage of Meyer. I can remember that there are new findings, but what is it again? I can only find Lemon x Orange.