Hybrid Persimmons Future Look Great

General Fruit Growing
987

Is it possible Gora Roman Kosh is one of the weird ones which might exhibit PCNA type tendency under certain conditions and not others while still being PCA as @Arhus76 suggests? I believe I read on nuttrees.net a similar observation that it sometimes has non-astringent crunchy fruit.

*Correction - it reads no astringency when ripe, vs another listing for Gora Rogers which mentions it needs to be soft to lose astringency.

Some other discussion on PCNA varieties in the Pacific Northwest recently seemed to suggest that even known PCNA varieties may remain astringent if temperatures/conditions are not conducive to fruit growth. I think it might have been @ramv who made that observation?

Maybe GRK has enough non-astringent genetics to exhibit that tendency under certain conditions?

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988

It seems to me that PCNA exists in a continuum. It isn’t that something is purely PCNA or purely PCA. Different persimmons show an ability to neutralize the tannins to varying degrees. Some are able to do so more than others.
Gora Roman Kosh might be high on that continuum. I’ve noticed that Nikita’s gift can be non astringent even while being quite firm. (though not crunchy like Stan’s fruit).
Others are quite astringent until they get completely mushy (Hachiya, several American varieties)
Neither Gora Roman nor NG appear to have the known PCNA varieties in their parentage and yet produce very pleasing fruit. I suspect people will be quite happy with fruit like this and others that are undoubtedly on the way.

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989

Japanese and Chinese scientists have noted in published research that J-PCNA varieties may not completely lose their astringency in cooler (typically northern) regions. So Ram’s observation is consistent.

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990

Two NA variations are well-documented.

  1. J-PCNA persimmons appear to have 6 copies of a recessive NA gene. As far as I’m aware, non-astringency has NEVER appeared in a cross between a J-PCNA variety and any other variety with no J-PCNA ancestry. JT-02 is an example – 3 NA genes are not enough. There is a contributor to this forum who claims that 5 genes are enough, but he hasn’t shown evidence.

It is true, as discussed above, that J-PCNA fruit is not always completely astringent. I think the right way to describe this situation is that 6 NA genes are NECESSARY for the Japanese version of non-astringent; but 6 NA genes are not sufficient. Warm temperatures seem required. as well. In cool conditions, the NA genotype may not express as an NA phenotype.

  1. C-PCNA persimmons appear to have at least 1 copy of a dominant gene. Only one NA gene is necessary for the Chinese version of non-astringency. Maybe other conditions are important here, too.

Other NA variations have been discussed but these have nothing to do with #1 & #2. For example:

  1. Among American (D. Virginiana) varieties, a few are said to be non-astringent, as least some of the time. The best example I know of is Morris Burton. I have no personal experience with MB, so I am relying on reports from others. The mechanism of such early non-astringency in a DV variety, if it exists, is unknown. We know that it cannot be directly related to J-NA or C-NA traits.

  2. Among hybrids, similarly, a few are said to be non-astringent. The best example I know of is Gora Roman Kusch. Again, I have no direct experience. Given its provenance, it seems impossible that GRK has many (if any) J-PCNA genes. It also seems impossible that GRK has the C-PCNA gene since if it did, then one of its parents would have been non-astringent (which it presumably wasn’t.

An intriguing possibility is that the non-astringency sometimes seen in American persimmons or Ukrainian hybrids is not genetic but environmental. Just as genetic PCNAs sometimes fail to lose astringency due to environmental conditions such as cool weather, maybe genetic PCAs sometimes lose astringency early due to environmental conditions.

At any rate, we seem to need a lot more data about the DV and hybrid examples before we can know anything.

p.s. Richard – I know you will object to my use of the terms “dominant” and “recessive” in describing the genes in the C-PCNA and J-PCNA varieties. But those are the terms that the Chinese and Japanese scientists use.

991

While I am not an expert, I am skeptical of literature pointing to this NA gene without them providing clear evidence of how this gene was isolated. Where is the proof that there is a cause-effect of this gene on non astringency?
I’ve read the paper where this is mentioned as gospel but how was this gene isolated? Did they specifically edit this gene out to show that the offspring becomes astringent without the presence of this gene? Did they subject it to random mutations?

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992

@ramv – Read this. Tell me if it answers your question. I’m not offering it as proof, just as one article that may tell you what you want to know. Maybe people with more technical knowledge can evaluate.

2327-9788-article-p59.pdf (615.1 KB)

p.s. This is very recent. Focus on genome of PCNA persimmons. But you’d have to buy it, which I haven’t.

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994

At a recent conference here in San Diego, researchers from the world’s leading plant genomics center stated there is currently no methodology available for doing so with persimmon.

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995

When a biopath is turned off, it is almost always a biopath enabling regulatory gene which has been disabled. To prove the “ast” gene is responsible for NA phenotype, they would have to start with a normal PCA variety and “knock out” the suspect gene. This is highly complicated by the hexaploid genome. It could probably be done with crispr, but would likely take thousands of attempts. It goes without saying that a method of tissue culturing persimmon cells into viable plants would also be required. Then there is the complication that nobody has published the DNA sequence of the purported gene. It is absolutely required in order to produce an anti-sense section of DNA to block expression. The methods to do what you ask probably don’t exist… yet!

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996

I seriously doubt it because they would have to design a subsequence that does not match unrelated variants, of which they have no means of detecting or isolating in persimmon.

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997

Why do we need proof? We make lots of pragmatic decisions under uncertainty (e.g., will it rain today?). Usually life’s decisions are based on weighing the odds.

Here I’m primarily interested in a very pragmatic question – What is the best path to a cold-hardy, tasty, but above all non-astringent persimmon? I can’t disagree with an argument that we have no proof of the relevant genetics. But given uncertainty, where should we place our bets?

The two best bets would seem to be (1) a C-PCNA x DV cross; and (2) a JT-02 x J-PCNA cross. If non-astringency is the goal, any other approach seems likely to fail.

998

It’s ok to have questions that cannot (currently) be answered. - R. Feynman.

Considering that you have stated this is a problem for someone else to solve, I don’t believe that “we” is appropriate in your sentence.

999

This is childish. You should try to say something substantive and constructive.

As you know, my preferred approach involves a cross of JT-02 x Taishu. I am growing JT-02 but (1) I can’t get my hands on Taishu sticks. And (2) if I could, Taishu would not survive here (e.g., last night was -6 F). And (3) if it could survive, roughly 5% of the offspring of a JT-02 x Taishu cross would be NA, so I might need to grow 500 seedlings to end up with 25 for evaluation, and I don’t have that much land.

So the only way that I can be helpful is to make suggestions. Sure I said “we” because we are a community. But if I had written “where should you place your bets,” I’m sure you would have found the phrasing imperious.

What I may actually be able to do is to cross-breed D. Virginiana varieties to develop a non-astringent (or less stringent) cultivar. Along those lines, I recently started a thread exploring whether this might make sense, starting with Morris Burton. You quickly dismissed the thread as "not constructive’ without any substantive comment.

Meanwhile, I wait patiently for you to make any constructive suggestions.

Let me ask you: What are your two best suggested strategies for any grower interested in attempting to breed a cold-hardy, tasty, non-astringent persimmon?

My Plan A, as you know, is to back-cross JT-02 x Taishu. One of our colleagues ambitiously suggested crossing JT-02 with any and every J-PCNA that bears male flowers, and I’m happy to endorse that broader plan. The key is to get the J-PCNA gene on all 6 of the hybrid’s chromosomes.

The main obstacle to such a plan is that only ~5% of the offspring will be non-astringent. So we (!!!) would need to test a lot of seedling trees.

My Plan B would be to cross the C-PCNA Luo Tian Tian Shi x any of the better D. Virginiana varieties. The key is to get the C-PCNA gene onto at least one of the hybrids chromosomes.

The main obstacle to this plan is that it would probably require embryo rescue, so it is beyond my capabilities. Assuming the C-PCNA gene functions as usual within a hybrid genome, at least 16% of the trees should be non-astringent. So we’d still need a lot of trees but maybe only 1/3 as many as in Plan A.

I freely admit that we have no guarantee that either approach will work. Kaki genes may not function as hoped in a kaki x virginiana hybrid. This is just my best shot.

Now it’s your turn. Many of us who live in the northern U.S. would like a cold-hardy, tasty, non-astringent persimmon. What should we do?

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1000

It would be more helpful to stop posting lengthy speculations. Further, to my knowledge you are unqualified to advise anyone on hybridization of fruit trees.

Those who are interested in experimental evidence can consult the astringency reports published by Olga G. for the large number of crosses produced in the Ukraine.

1001

Well, we’re almost all rank amateurs. Are you gonna start canceling everyone who doesn’t have a relevant PhD? The forum will be healthier if we judge ideas on their merits. My Plan A and Plan B are out there to stimulate thought and discussion. The world of experts can criticize.

I am interested in the Ukrainian work, which is why I started a thread on the topic a few weeks ago. But the Ukrainians have not been especially interested in eliminating astringency. Their stated focus was on improving cold hardiness, which is why they performed so many crosses using American varieties, which are all astringent.

You’ve looked at the Ukrainian “astringency reports.” Can you point to any hybrid that is both cold-hardy and non-astringent? From what I’ve seen, the Ukrainian crosses fall into two main categories: (1) some version of PCA Kaki x PCA Virginiana [the Rosseyanka family], which may be cold hardy but are not non-astringent; and (2) various Kaki x Kaki, which may be non-astringent but are not cold-hardy. So how does this evidence guide us?

This is not “lengthy speculation.” You’ve told us to look at the evidence. What does the evidence tell us to do?

1003

Hybridization of fruit trees is nowhere as simple as you would like it to be. A PhD is not necessary to comprehend it, but years of experience observing breeding and studying the outcomes is certainly a requirement to providing viable advice.

This conjecture of yours contradicts the publications of the Ukrainians, which I believe are all in the public domain.

You are not breeding anything, so it is not relevant to you.

For persons seeking advice I have started this thread: Breeding Methods for Fruit Trees

1004

Gentlemen: let’s give each other the benefit of the doubt and, above all, treat each other with the kindness and respect that are hallmarks of this fabulous site.

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1005

I agree that hybridization of trees is not simple, especially when we are mixing pollen and genes from two different species. That’s exactly why I made my suggestion that we back-cross JT-02 x Taishu – it seems likely to work to produce a PCNA hybrid in a single generation!

My friends on this forum are almost all amateurs, as am I. I view these discussions more like brainstorming over beers than conferring at a scientific conference. Many of these friends are cross-breeding trees, which as you say is difficult. Much of the effort seems random to me – one contributor compared it to a casino. I’m just trying to nudge these friends in a less random, hopefully more productive direction. If they don’t appreciate the nudge or like the suggestion, they can ignore it.

Here are some prototypical crosses that illustrate the issue. Please keep in mind that I am prioritizing non-astringency:

  1. Many David Lavergne crosses were PCA/PVNA Kaki x F2 Rosseyanka. These produced at least one awesome cold-hardy hybrid – Kassandra – but nothing non-astringent.

  2. Many Ukrainian crosses were PCA Rosseyanka or PCA Nikita’s Gift x OP Kaki. These produced some interesting somewhat cold-hardy hybrids, but nothing non-astringent.

  3. Jerry Lehman crossed PCA Josephine (DV) and PCA Nikita’s Gift (hybrid) x PCNA Taishu (kaki). The crosses with Nikita’s gift are forgettable, not especially cold-hardy and still astringent. The cross with Josephine produced JT-02, which is cold-hardy due to the DV contribution but also still astringent because the J-PCNA trait is recessive.

What’s the bottom line? Random crosses give random results, all PCA. We’ll never get a non-astringent J-PCNA x DV hybrid unless there are J-PCNA genes in both the female and the male. Like JT-02 x any PCNA male.

It’s a tangential point but you can tell that the Ukrainians did not prioritize non-astringency based on the varieties they’ve chosen to hybridize – it’s almost entirely PCA kakis and PCA virginiana and PCA hybrids. In 100 years or so, they have not produced a single NA hybrid, and I don’t think they care. If we follow the same paradigm, we’ll end up in the same place.

I’ve said my piece. I’m gonna drop this discussion now.

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1006

@jrd51
I believe you have made the common error of confusing crossing with breeding. Worldwide, the effort with persimmons to date has focused on methodologies for crossing species – which has proved a difficult task. In addition quite a bit of work has been performed in cataloging the results in terms of astringency, cold hardiness, and several other properties of the fruit and trees. All of this information is important in the design of a breeding program.

Breeding programs for perennial fruits are a long term process due to the turn around time in maturation of the seedling into a mature tree with stable properties. Like many other fruits, the generation interval for persimmon is 8-10 years and breeding programs are designed with roughly an 80-year lifespan. Along the way interesting cultivars emerge but it is prudent to wait until the entire program has been completed. In my personal observations this has proven to be the case with Citrus and Prunus.

Patience is a virtue - Prudentius

1007

Slightly off topic, but has anyone here grown Cape Wild Persimmons - a dwarfish cultivar from the Baja region i believe. Not cold hardy, but shrub sized which seems useful? I ordered some seeds from Trade Wind Fruits, so I will see how it goes. Hopefully i can germinate them.

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1008

Joe,

Taishu is coming to America this summer. In the next few years we will cross the male flower with lots of hybrids including JT-02 and the Gora series. We just have to wait about 5 to 10 years to see what are the offsprings are like. Taishu graft will take atleast 2 to 4 years to produce flowers then we will take Taishu male flower and back cross to JT-02 and other hybrids then grow out their seeds in pots for one year then take their scions and graft to the large undertocks for a faster fruit production which takes another 3 plus years or so and it is not a guarantee to get a female tree. In the history of breeding there were more male trees than female trees in breeding persimmons. I spent the last 5 years breeding hybrid persimmons and only got one generation going and there are lots of seeds to be planting in pots this April for more first generation hybrids. It is a very time consuming process of breeding hybrid persimmons. I am almost 60 years old and Dax is not that far behind and We are hoping to get some of these great tasting, large fruit hybrids and super coldy for growers in Z4 and Z5. In addition, we hope someones will have to continue our work for future super cold hybrids breeding.

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