The Tropical Fruit Forum

Some research I was able to dig up:

George A. Zimmerman undertook an 18-year project to breed pawpaw, attempting to produce intergeneric hybrids by crossing Sugar Apple (Annona squamosa) and atemoya (A. squamosa x A. reticulata) with Pawpaw (Asimina triloba). He was unsuccessful. But he did successfully create interspecific
hybrids by crossing Asimina obovata, A. longifolia, and Asimina reticulata with Asimina tribola. The A. triloba x A. obovata hybrids appeared fertile.
Unfortunately, Zimmerman died in 1941 before his other crosses matured.

Pawpaw Variety Development: A History and Future Prospects, R. Neal Peterson,
Horttechnology, July-September 2003

For me it is laughable  to read such proposition from somebody  that has no first-hand experience in it.

It's not my fault none of my plants have reached fruiting age.
We're not all so lucky to have huge fruiting bushes like you, Ilya.

Here is an update on my dunstan citrumelo x ixs seedlings.

What does ixs mean?

I'm going to attempt to cross Green Gage plum (6n) with Sweet Cherry (2n), which should result in a 4n chromosome offspring.
 Then cross that with sour cherry (4n), in this case Juliet in the Romance series of cherry hybrids.

Definitely leafminer. They target the younger leaves.

I've started TaiTri and Citrumelo seedlings and will evaluate their hardiness in the meantime.

There's no chance Citrumelo is going to survive for you in 6b. TaiTri might.

I do think Citrumelo is, generally, just a bit hardier than Citrange, but you are going to need a lot of seedlings to show any that exhibit exceptional hardiness, similar to the citrange trial you have already carried out.

Considering that you are in 6b, I could see the reluctance to use C. ichangensis in hybridization. Even C. ichangensis simply isn't hardy enough where you are.

To your question concerning C. ichangensis....I did not keep it because of its weak fruit quality.

I think C. ichangensis may have much value for hybridization because it's the only fruit that does not have poncirus bitterness and is still fairly cold hardy. If you crossed it with something like citrange you might get something useful.

The one from the left looks like Kaffir lime. The round leaf. Do they have a strong strong smell when you crush them?

I'm growing several Kaffir lime seedlings too. Yes, the leaves look nearly identical to Ichang papeda with their symmetrically sized winged petioles.

I'm pretty sure these cuttings did not come from from Kaffir lime, not unless a Kaffir lime tree could have survived outside in Portland, Oregon this Winter (took the cuttings myself).

As for the smell of the leaves, they have a nice fragrance, very light, lemony, but with a characteristic deepness reminiscent of Yuzu. (It doesn't have the spiciness of Yuzu though) It smells a little different from Kaffir lime leaves, but similar in the fact that the smell of both is very light and mild, without the harsh smell of petitgrain found in other citrus leaves.
I mean probably mild enough to cook with (like Kaffir lime leaves), though it probably wouldn't add much flavor.

For whatever it's worth, I have a little N1tri seedling.
It doesn't look the best and hasn't been growing well or growing very fast.

Citrus taiwanica might be able to handle heat (if kept well watered). Changsha mandarin can handle drought. Neither is very good eating quality.
Duncan grapefruit is said to be very cold hardy, and grapefruits can handle some higher temperatures. The young plant is still going to need to be kept shaded though, in the heat.
Bloomsweet grapefruit may have more hardiness but slightly lower eating quality.

Australian lime can handle desert conditions, might be the best option.

Orange Frost/Arctic Frost are other options, they're hybrids between Changsha and Satsuma. Still are probably going to need shade or planted close to other trees to provide some shade.

The Satsuma now appears dead too.

So it appears that a small sized Satsuma on dwarf rootstock, covered by a clear vinyl plastic enclosure, was not able to survive.
An Arctic Frost growing on its own roots, not protected, in a kind of shady spot, which was moved outside a little too early in early March with very cool but not freezing temperatures, died back and then recovered, was not able to survive either.

But this was definitely a colder Winter than usual. Snow 16-18 inches deep (which is unusual here) and temperatures in the yard that I estimate went down to about 14 F.

It is in zone 8a, but in the Pacific Northwest where temperatures do not really begin consistently rising until very late April.

The Arctric Frost might have done better if it had been grafted onto trifoliate and if it had not been growing inside and suddenly transferred into the cold outside in March, which resulted in a fair amount of die-back due to the sudden transition, which may have put it in a position not to be able to handle the following Winter as well. Perhaps planting it in a warmer sunnier spot might also have helped.

For comparison, the Yuzu on dwarf rootstock (probably the same rootstock variety because same nursery) survived, still has retained a few of its leaves, although it looks like it has gone through an ordeal and there is just a little bit of branch die-back at the extremities.


What I think this proves is that an Arctic Frost is not going to easily survive a cold winter in the Pacific Northwest region.

This is of course a very different situation from Texas and the South.

I would say it looks like the roots are not able to supply enough water to the leaves. That could either be some sort of root issue, or a very blazing hot period of weather. It might benefit from just a tiny bit of shade cover of some sort.

Blech. I do not like the Japanese persimmon. It is very astringent, and resinous, and disgusting, tasting like rotten vomit.

Surely that must be an exaggeration.
The Fuyu variety is a lot less astringent than the Hachiya, which is really more appropriate for drying out and preserving.
You must have had an astringent persimmon that was way overripe (blotting).