Yeah, Japanese and Korean breeders have long complained about the adverse results of inbreeding among J-PCNA varieties, which started out inbred and just get worse with every J-PCNA x J-PCNA cross. And decades of breeding have seemingly produced very few significant improvements over Fuyu, Jiro, and their bud sports.
I’d love to see what happens with a back-cross of JT-02 x Taishu (J-PCNA). We’re so close, and both varieties taste good. But the fast track to a non-astringent persimmon with “more American genetics” would be through the C-PCNAs – IF . . . IF . . . IF the C-PCNA gene works in D.V.
See Fig 3 & 4 to get a sense for how inbred J-PCNA hybrids are. Everything displayed traces back to Jiro, Fuyu (and a budsport), Okugosho, Hanagosho, and Fukurogosho.
FWIW, my own reading of release reports suggests that the best choice for short-season growers is Soshu, but I have no data on cold-tolerance.
From an uneducated perspective, adding DV to the genetics should drastically reduce the amount of any inbreeding issues, correct? Even if it was a few related DV crosses?
Reading some of the linked articles confirmed my speculation that inbreeding would be a problem. Yes, in any cross with DV x DK, inbreeding would be at a minimum, however, this cross is far enough apart that there would be genetic issues to resolve which could include chromosome inversions, translocations, and fertility problems.
Based on current information, Morris Burton, Prok, and Early Golden (or offspring) have very high potential in crosses with DK. Morris Burton because it brings a novel NA trait into the mix. Prok because it brings very large size. Early Golden for fruiting and flavor traits and tendency to produce male flowers. I don’t know the genetics behind the Russian made crosses between DV and DK so it is hard to say if they carry enough potential. IMO, the necessary genetics are available to make some potentially major improvements, but they are still locked up in different species and particularly locked up in female only varieties where a male is needed to make useful crosses.
I concluded Prok today. Unlike @jrd51 I have eaten Prok before it was fully ripe and it had some hard aspects to its fruit off the tree as I picked and ate it. It was not-astringent.
Unfortunately I don’t have it in my yard, but… at Red Fern Farm this happened on many Prok’s I ate during one summer visit of several visits.
Prok is not large. It may be large relative to the average wild American – it’s the only American I grow, so I can’t be sure – but it is small relative to Asians. My IKKJs seem 3-4 times as large. JT-02 appears 2-3 times as large.
Early Golden is reported to be the American variety used in Ukrainian hybrids. I’m not aware of any disclosures about variety names of either DV or DK parents.
Maybe something about your growing conditions caused a radical difference. If so, that would be more valuable to know than anything about persimmon genetics.
FWIW., my Prok begins to ripen in late September and continues through November. Any even slightly unripe fruit are so astringent that you can’t spit hard enough. Your tongue, cheeks and teeth get coated with a sticky sediment. It’s not just me – I’ve had at least a dozen people try the fruits at full ripeness plus or minus a little.
Nope, Tom doesn’t think I know what the hell I’m talking about.
He said, “There is a firm (but not crunchy), non-astringent persimmon called Geneva Long. It is one of the few that can be sliced like a tomato when it is ripe and ready to eat. It is probably very hardy, too, as it was bred in New York. That might be the one you’re looking for, for breeding purposes.” (Tom Wahl)
Well, it was purchased from Stark. Are you aware of them having any issues with this name?
Not large: I said not large compared to my IKKJ. Similarly, JF&E (see link below) says “large for an American.” See the picture below for a sense of size.
So astringent: I’ve never heard anybody say that Prok was not astringent.
Continues through November: Is that unexpected? JF&E describes Prok as early but then says “ripens in November”
I agree that my fruits have a different shape than the one Dax posted. His seems more oblong and smaller. Red Fern Farms describes Prok as the “largest of all American persimmons.” If that’s the metric, then mine is more likely to be authentic.
Dax’s photo is labeled “Prok'.” Is #39 another variety and, if so, could that be what is pictured?
Your fruit seems similar to mine. Some of mine are flattish on the bottom, some are roundish. I couldn’t tell the difference between your fruit and one of my roundish ones. Note that my fruits are all upside down in the container so what you are seeing is the bottoms.
No, I haven’t tasted anyone else’s Prok. Other growers, especially in cooler areas, have described Prok as sometimes bland. Mine is similar in that respect.
I’d consider the possibility that what I have growing is the seedling rootstock, except for 2 things. First, I remember seeing the graft and all growth is north of it. Second, I had seeds in some fruits this year – maybe a dozen seeds total in well >500 fruits. As far as I can see, there is only one possible source of pollen: I’ve let a few suckers grow so that I can use them as rootstock. The suckers may have produced male flowers. If that’s the case, then the rootstock is male – not Prok.
p.s. See the photos here. That’s exactly what I’m growing.
Okay, a bit off topic, and I haven’t been keeping fully current with the discussion, but…
Would it be easier to breed a hybrid for the trait(s) that allow astringency to be removed with simple treatments like alcohol, CO2, or vacuum - like can be used on PCA kakis?
Thanks for raising that idea - I was wondering about that as well. I’d be interested in which existing hybrids respond at all to these treatments. I’ve only tried Nikita’s Gift with CO2, and it didn’t seem to affect the astringency at all. Can anyone share their experience with other hybrids?
