Yuzu x keraji certainly does sound promising.

Thanks for the link. I don't like the many names either but at least it is becoming available in Europe.

This could be an interesting cross and probably pretty coldhardy but as far as fruit quality goes just get the right Yuzu, which is excellent.

Seems to be only monofoliate now, right?

Quick update. The fruit is actually good to eat when the rind is still greenish so I picked two today.
 

For comparison a large(ish) navel orange. Are these spots frost damage?

I still have some fruit on my ichangensis x sinensis. We are expected to see -4/-5C the coming nights.
They have already seen a few -2/-3C and still look pristine.
Will they wrinkle or fall off or something like that when damaged by frost?

Thank you Socal, for posting that image of my tree. 
I harvested the fruit on that in mid-November.  About 6 lbs.  They range in size from sub-ping-pong ball to medium size Satsuma.  The flavor is good, but rather sour.  Ripeness varies considerably.  The ripest ones have 'squishy' peels and peel rather easily, though not so easily as Satsumas.  Since snow flurries are occurring, I think I'll stay indoors and use the time to do a Brix and Acid level reading this afternoon, using the smaller ones.



I apologize for the blurriness of the image, but I ain't no photographer.  The fruit above the ruler are some of the Citsumas; I've eaten the largest few, and juiced a few others for a Chinese dish.  The three fruit on the bottom of the image are typical LA Early Satsumas, to provide scale, along with the blurry ruler.

Thanks for your comparison, Jim! May I ask if your Prague is a regular bearer? Has it ever had trouble fruiting?

I forgot to measure it but it weighed exactly 70 grams.

I once found a single seed in a Sweetie and planted it. It has flowered this year for the first time after around four years from seed but hasn't fruited yet.

Just wanted to show you my seedlings of a Sacaton citrumelo. This one is know to have a very high percentage of zygotic seeds. In fact, only Nr. 2 looks like a nucellar plant to me, 3 and 4 are completely monofoliate.

Nr. 1


Nr. 2


Nr. 3


Nr. 4


Nr. 5


On one hand, this is excellent for breeding purposes but on the other hand, Sacaton Citrumelo is not a very good Citrumelo. It has a very strong Poncirus taste, much more so than others I have tried and it is rather small.

I picked the fruit in Eisenhut's nursery so the pollen donor could have been anything. There was a Yuzu nearby but also an Oronules, some sort of Changsha, a Thomasville and others.

I have never seen FD or poncirus hybrids ever come out of dormancy with just a  couple days of warm weather.  It often takes a week or more of warm weather to bring them out of dormancy.

Same here. However, this year, snow in May did kill a lot of flowers but that's another story.

Another super dwarf would be the match and rosette type seedlings. I found two rosette type seedlings among my FD seedlings last year.
https://www.jstage.jst.go.jp/article/jjshs1925/63/1/63_1_23/_pdf

If you want to go for larger ones:

Here are some on sale: https://www.lubera.com/de/artikelsuche?query=poncirus

Also: https://www.zitronenlust.de/pflanzenkaufen/Zitruspflanzen/frostharte-Zitruspflanzen-55/Bitterorange-Poncirus-trifoliata-192.html