A quick dive into history won’t hurt, I guess. “Persimmons for Everyone” a book written by Eugene and Mary Griffith with additional chapters by J.C. McDaniel was published 40 years ago. It was the time when James Claypool was active in breeding. The book is mostly full of recipes, but Mr. McDaniel wrote some review on the cultivars available at that time as well as his attempts at hybridizing. I had obtained the print copy from late Jerry Lehman some 10 years ago. Here are few excerpts from the book:
This documents your point that it is basically impossible to cross virginiana x kaki without extraordinary measures.
Would you agree then that the shortest path to a full PCNA hybrid would require two steps: (1) create a virginiana x J-PCNA kaki cross by whatever heroic means necessary, then (2) back-cross the offspring to a J-PCNA kaki, which you report is an easier.process, provided the kaki produces male flowers?
In all cases, any resulting PCNA hybrid would be 75% PCNA overall (though homozygous for the PCNA allele). The other 25% would represent the grandmother. For example, the JT-02 hybrid daughter would be 75% J-PCNA (Taishu) and 25% Virginiana (Josephine).
Another approach would be to work with an existing Virginiana x J-PCA cross. This would then require two crosses with a J-PCNA variety, but perhaps without any heroics. For example, a hypothetical Kassandra hybrid daughter would be 75% whatever J-PCNA is used and 25% Kassandra, which means 12.5% J-PCA (Great Wall), 6.25% whatever Virginiana was used in Rosseyanka, and 6.25% whatever Kaki was used in Rosseyanks. Sound right?
Was it on me? Well, I think we can skip the point (1) assuming that we already have JT-02…but I am still not 100% sure what it is. I have it, we all have it, but there aren’t any recent photos of a fruit in detail and the tree with fruits. I’ve started to graft it by topworking old virginiana trees to speed up the process. Last year few fruits were set in container plants but they dropped off before ripening. Nonetheless, they seem to be good sized, Branches have this funny zigzag structure which I haven’t seen in other hybrids.
So, your point (2) seems to me as the way to go. Not sure about repeated backcrossing with Taishu, though. I’d try to make some simultaneous crosses with other PCNA kakis: Tam Kam x Taishu for example, in order to get another monoecious PCNA. This would serve as an alternative pollen donor and may also contribute with some improved hardiness.
You don’t accept representations that JT-02 is a cross of Josephine x Taishu?
I like the idea of additional crosses of Taishu x J-PCNA (e.g., Tam Kam) to create an earlier-ripening, more cold hardy pollen donor.
p.s. Re #2, the Korean breeding program has released at least 5 new PCNAs with Taishu as the male / pollinator – Gampung, Jowan, Wonmi, Wonchu, and Fantasy. I have no idea whether any of them is monoecious.
I hate to be the party pooper, but I should point out that even if you got a non-astringent hybrid, it could taste like a dud.
I tried a few pounds of different hybrids from persimmon collector Don Compton’s place. Ross and Kassandra were rather uninspiring to me (decent size though). I’ve had tastier D. Virg. Nikita’s Gift was stellar in comparison - rich, flavorful, good sweetness. NG is probably only hardy to zone 6b.
The original purpose to use D. Virg was to confer BOTH benefit of hardiness and flavor. If you only hit one objective, then you’ve still missed your goal. If you want non-astringent, you really need to hit all three for it to be a superior alternative to existing hybrids.
<< I hate to be the party pooper, but I should point out that even if you got a non-astringent hybrid, it could taste like a dud. >>
Sure. But with that attitude we’d never discover anything. Thomas Edison would have studied accounting. Columbus would have sat on the “dock of the bay” in Genoa.
We acknowledged above that any new variety could be a dud. That’s why we discussed above a need to try 2000 or more seedlings from any particular cross.
<< The original purpose to use D. Virg was to confer BOTH benefit of hardiness and flavor. If you only hit one objective, then you’ve still missed your goal. If you want non-astringent, you really need to hit all three for it to be a superior alternative to existing hybrids. >>
I’m not going to be doing any of the actual work.
But to my naive mind, the goals seem achievable. Reportedly JT-02 is far more cold hardy than any Asians or hybrids. Taste is personal but JT-02 is reportedly very tasty and sweet. If a back-cross of JT-02 with Taishu results in fruit that is (1) non-astringent, and (2) otherwise merely an average of its parents, that will be a huge success. It would be roughly a non-astringent version of Nikita’s Gift. With thousands of seedlings, it seems very possible to do better.
The other feature that you ignore is texture. A lot of people dislike the gooey consistency required of a fully ripe (no longer astringent) PCA Kaki or Virginiana. A non-astringent hybrid would be edible before it turns to snot. And because it could be picked before it has turned to mush, it could possibly be stored longer too. Maybe even shipped.
Fair enough. Agreed, texture is another one to hit on but that also goes hand in hand with nonastringency. Thus, I would say that is secondary side benefit. Unless you hit hardiness, flavor, nonastringency and texture is kind of a bust pursuit. Let me explain why.
Cliff has probably the most extensive collection (excluding the Lehman property) of hybrids in the US and maybe EU at the moment. He has at least one of the new Gorvela releases from Europe. Many of these are cold hardy reliably to 6b. Many are border line even at 6a.
Basically, many hybrids are no more hardy than kakis. If that is the case and you want a crispy nonastringent persimmon, why would you bother with a hybrid if you can grow a straight up 100% kaki that is significantly larger? If the hardiness is the same, surely a larger fruiting kaki that is a proven nonastringent type is a better choice.
The hybrids [and more specifically the possibility of a nonastringent hybrid] are attractive to a specific type of people. It’s for people in zone 4, zone 5, and zone 6a. They cannot grow a kaki outdoors without a lot of consideration for microclimates and perhaps additional protection. Kakis are out of the question. Thus you need to address hardiness first. That means it will survive. Second, you need to hit flavor. Plenty of hybrids aren’t more tasty than D. virg. They are passable and get proper attention because they at minimum offer superior size.
A good example would be Nikita’s Gift. It’s reliability hardy to 6b. 6a will still see some winter damage depending on the severity of the winter. Even if NG was nonastringeny, it would be kind of moot, because it’s not hardy [enough]. In fact, of those three traits: hardiness, flavor, nonastringency, it only has one advantage - flavor. You can [for the most part] get away with growing a kaki outdoors if you can grow NG without any winter damage. So why grow a NG then? Explains why it’s not particularly popular.
Once you address hardiness and taste, then you have the ability to address nonastringency. It’s a tall order, though not impossible. Likely this would involve techniques like embryo rescue (which Jerry even used for a few of his introduced hybrids). It’s not as simply as just making hand crosses.
Cliff shared this photo on facebook not too long ago.
I’d really love to see this thing cut open. Also a grower in Missouri posted a YouTube video showing some JT-02 fruit.
I agree with pretty much all of that, which is a good thing because you clearly have more knowledge and experience than me. I’ll just add a few more optimistic points:
As far as I know, all hybrids except JT-02 involve crosses of astringent Virginiana X astringent J-PCA Kaki. So the quality and hardiness of those hybrids seem interesting but may be irrelevant here.
JT-02 – as far as I know the sole cross of astringent Virginiana X J-PCNA Kaki – is already very cold hardy and tasty. So the battle seems half won. You don’t mention JT-02, and maybe you agree with Pavel that the case isn’t entirely proven. But if JT-02 lives up to its press, then the main immediate challenge would be to cross JT-02 with some J-PCNA Kaki and produce a new hybrid that picks up full non-astringency while retaining sufficient cold hardiness and taste. Even if it takes 2000 or 4000 seedlings, it seems do-able. My understanding (anyone please comment) is that crosses of JT-02 x Taishu would not require extraordinary measures.
While I enjoy the non-astringent IKKJ that I grow here (borderline Z6B/7A), I would jump all over any non-astringent hybrid with even better flavor. I see no reason why home growers and consumers across all USDA zones wouldn’t feel the same. People across the U.S. eat millions of Fuyu/Jiro fruits – why not a Fuyu/Jiro granddaughter with enhanced flavor? Think of such a non-astringent American-Asian hybrid not so much as a more cold hardy PCA but as a more flavorful PCNA. Not only would it be it non-astringent but also you could pick it before it gets mushy – and then either eat it immediately or ripen it on the counter (no CO2 / alcohol). All of that should have appeal to growers in warmer zones than 6B.
Looking down the road: Suppose that some of the non-astringent offspring of JT-02 x Taishu (or any other similar [V x PCNA] x PCNA cross) are monoecious. That would open the door to new crosses of a new JT-02 hybrid with other hardy and tasty American varieties (e.g., WS 8-10, H63-A, D-128, Morris Burton). Within 2 generations, the flavor and hardiness genes of these superior American strains would be incorporated into a new fully non-astringent strain.
I think for #3, I would point to current breeding work where they take astringent kakis and cross with nonastringent kakis like IKKJ x Nishimura Wase. It’s much easier to skip the benefits for hardiness all together from D. Virginiana and disadvantage of smaller fruit size.
Japan and China are already breeding more nonastringent kakis. The advantage of using D. Virginiana is very specific for places colder than zone 6b/7a. The downside is smaller fruit size and more difficulty in getting crosses to fully develop, hence why you need to resort to embryo rescue.
With 100% kaki, you can hand pollinate, get seed, and then plant. There are no compatibility issues. It’s much simpler and straight forward. If it’s never going to go into a colder region, what’s the point? You’re gaining hardiness at the cost of smaller fruit.
D. Virginiana can get really small. Once you throw those genetics in the pool, there’s nothing to say you couldn’t end up with a 1.5" nonastringent hybrid. That’s a small fruit.
The advantage and holy grail for nonastringent hybrids is really for cold regions. There are very flavorful kakis and they would be a much better parental candidates for nonastringency, requiring fewer crosses to achieve said target.
From what I’ve seen of public releases, both the Japanese and Korean programs have focused on PCNA x PCNA crosses. There are a few PCNA x PVNA crosses, which produced PVA offspring.
So yes, the Japanese and Koreans have been producing more PCNA (PCNA x PCNA) hybrids. But they are reportedly frustrated because the PCNA gene pool is so narrow that few of the hybrids is a notable improvement.
Maybe you have access to other (unpublished) results. I say this with all seriousness – Can you point to good varieties released by either the Japanese or Koreans that resulted from PCNA x PCA crosses?
To be perfectly honest, I’m not really sure. Recently, I have been pouring over ziphus and castanea sp. research for @castanea. I haven’t had a chance to follow up on the diospyros research from china and japan lately.
What I would say is that more research is put into kakis and the hurdle to overcome to achieve nonastringent kaki is lower than the one for nonastringent hybrid or nonastringent virginiana. Not that it’s impossible, but barring serious effort, improving the flavor of a nonastringent kaki is a hell of a lot easier than selecting for a nonastringent hybrid.
Actually the fast way to breed one would be GMO. You can throw down what you want in a gene gun and you can shortcut your way to a cisgenic breeding.
I thought about suggesting GMO earlier. It may be possible to produce a knock-out variety by disabling 6 genes for astringency which would leave in place all the other breeding work for large good flavored fruit. The difficulty of doing this in the current regulatory environment is non-trivial.
GMO: I totally agree. The real future may be to insert genes for cold hardiness from Virginiana or flavor attributes from PCA/PVNA Kaki into a PCNA Kaki.
Note that the Japanese have been crossing PCNAs for 70 years (assuming that not much happened in the breeding program during WWII) and the Koreans for maybe 50. We have little to show for it.
Further to the above, a very good article on persimmon breeding:
<< Main objective of persimmon breeding has been to produce commercially attractive cultivars of the PCNA type which can be eaten without any postharvest treatment [[46]. Therefore, PCNA fruit are the most desirable for fresh consumption because it is not necessary to apply any postharvest treatment in order to remove the astringency. Hence, the breeding of new PCNA cultivars is the most popular objective in the entire persimmon growing countries. >>
<< Japanese PCNA cultivars are based on a recessive character and their genetic resources are very few. Repeated crossings within the narrow gene pool cause inbreeding depression, which hinders tree vigor, fruit yield and size. Therefore, studies have been ongoing to obtain new cultivars through the backcross (PCNA × non-PCNA) × PCNA since 1990. In 2007, ‘Taiten’ and ‘Taigetsu’, which are PVA cultivars, were derived from the cross of ‘Kurokuma’ (a local PVNA cultivar in Japan) × PCNA cultivar ‘Taishu’.
The proposed back-cross of JT-02 would be consistent with this (PCNA x non-PCNA) x PCNA paradigm. Yes, it crosses species but the hard part has been accomplished.
It would be very interesting to know whether the Japanese efforts with PCNA x non-PCNA kaki crosses have led to any successes other than the two PVA’s mentioned.
LOL – I think it’s because the article was published as a chapter in a book with a broader theme. Unfortunately, the link to the book doesn’t give access to all pages.
I would like to add to what Harbin has posted on the backstory to the Morris Burton persimmon.
I have been searching for some time for a contemporary newspaper report of the Burton persimmon winning the festival contest and just now found it, dated 30 Sept 1957. The fruit was entered by Samuel Oscar Burton (1886-1976) and named after his son Morris (1930-1976), a Korean War Vet. I am including here part of a 25 Sept 2012 newspaper article by Sam Burton´s granddaughter, Joyce Mundy.
