Your buds aren’t even swelling? I’m surprised if mine are ahead of yours.
Mine are just starting to swell. Super early this year.
Some of mine are still in the shade of the house or tool shed at this sun angle.
John S
PDX OR
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Not a bit of bud swell even here (persimmon and jujus). Like others have mentioned everything else is either budding, blooming or leafing out.
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The only thing here still dormant is apple.
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The only thing NOT still dormant here is me. I’m dying to get going.
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All my persimmon trees had buds open up this week and are pushing leaves - NorCal 9b
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You guess is right.
From this breeding study
Inheritance of Astringency in Japanese Persimmon.
A FuyuXPCA cross result in some PVNA offspring.
See page4 table 7
My own theory is Epistasis
IE hairless gene will surpress haircolor gene.
When there is no hair.It doesn’t matter what werid thing color gene is doing .
I believe that is what happeb to fuyu.
As a pcna variant it has no astringency.
So the pv gene can’t do anything.
From our perspective it will seems pv gene become recessive.
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Very interesting. I’ll have to give this table some close study.
Question: 61 PCNA x PCNA crosses produced 1007 seedlings. Of these, 26 (2.6%) were classified as PCA. This result seems highly anomalous. If the PCNA trait is recessive, then presumably all parents in the 61 PCNA x PCNA crosses were homozygous (6 NA alleles). But if that were the case, then presumably ALL progeny would have been PCNA.
It seems that perhaps one of the 61 PCNA crosses did not produce PCNA offspring. How could this have happened? I’m led to wonder whether one of the PCNA parents had only 5 of 6 PCNA alleles. But then why would the parent be PCNA but the children PCA?
The only explanation I can think of is that the classification system is unreliable, so some actual PCNA offspring were classified PCA. In the U.S., some growers have observed residual astringency in Fuyu when grown in some conditions (e.g., insufficient heat); maybe that’s the source of the unreliability.
Note: Fuyu appears to be the only PCNA in this 1985 study with a PVNA allele. Since then, Japanese breeding programs have used Fuyu as a parent. As a result, other PCNA varieties with Fuyu ancestry appear to have 1-2 PVNA alleles (e.g., Izu, Taishu).
Theoretically, PCNA×PCNA should only produce PCNA offspring; yet, PCA appeared in this experiment
There are several possible explanations.
It could be mutation—among the 1,006 seedlings, 17 were PCA, and I don’t think it’s implausible to attribute this to mutation.
After all, PCNA is a recessive trait; a mutation in just one of the six loci could result in a PCA phenotype.
Human error is also possible—someone might have mislabeled the samples,
this happen more then ppl willing to admit.
or there could have been a mistake during pollination. Perhaps an especially hard-working bee managed to get inside the pollination bag."
The hypothesis you proposed regarding insufficient temperature, in my opinion, is unlikely.
The experimental field is located in Hiroshima, which is in the southern part of Japan, where summer temperatures are sufficiently high. It is improbable that PCNA de-astringency would fail due to a lack of heat.
Fun fact: This actually happened in rice breeding. Taichung-65 is a daylight-insensitive variety, which is very important in rice breeding. However, when scientists examined the gene, they found that the gene controlling daylight-insensitivity was absent in both parents. Moreover, Taichung-65 has only 50% similarity to its parents.
It turned out that the gene came from a wild-type weed rice native to Taiwan. Somehow, the pollen got into the breeding lab and fertilized the plants.
some guy did;t do their job right 100 yr ago and let weed get into breeding program.turn out the that weed pollen is just the thing they need !
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Table 3 reports 759 progeny from crosses that are not PCNA x PCNA. Of these, 15 (2%) are classified as PCNA, which seems impossible if only PCNA x PCNA should produce PCNA progeny. So maybe something like 2% is a base error rate.
I’m gonna continue this analysis, hoping to test our understanding of the heritability of non-astringency in Asian persimmons.
Before starting, I should note certain difficulties:
First, classification of novel persimmon varieties as PVA or PVNA is fraught with problems. To distinguish a PVA from a PCA, both fruits must be well seeded. Differentiation is a matter of timing – the seeded PVA loses astringency (and perhaps changes color) a little quicker than the mature seeded PCA. Similarly, to distinguish a PVA from a PVNA, again both fruits must be well seeded. Differentiation is again a matter of timing – the seeded PVA loses astringency somewhat more slowly than the seeded PVNA. In both cases, it’s a judgment call. All of this suggests that the reliability of classification of PVA’s and PVNA’s is lower than for PCNAs and PCAs.
Second, it is entirely possible that a PCA, PVA, or PVNA variety carries 1 or more PCNA alleles – just not 6! These alleles are presumed to be recessive.
Third, it is possible that a PCNA variety carries one or more PVNA allele. Fuyu appears to do so.
All of these issues complicate inferences about the genetics of persimmon varieties based on breeding results.
That said, we can now move on to the actual results:
- PCNA x PCNA crosses should produce 100% PCNA offspring. This is based on an assumption that every PCNA has 6 NA alleles and 0 PV alleles. It is suspected, of course, that Fuyu has at least 1 PV allele; but the presence of any PV allele(s) should be hidden in a PCNA variety.
In this study, there were 61 PCNA x PCNA crosses, producing 1007 seedlings of which 964 (95.7%) were classified as PCNA. That very high percentage is consistent with our expectations – but it is not 100%. 17 persimmons were unidentified and 26 (2.6%) were identified as non-PCNA. Of these, 1 was identified as PVA, 8 as PVNA, 17 as PCA.
Production of PCA, PVA, or PVNA offspring seems to require astringency! Yet both parents in a PCNA x PCNA cross are totally non-astringent. There are numerous possible explanations, e.g., new mutations, human error. Crosses involving Fuyu could give the appearance of PVA or possibly even PVNA. But it’s tougher to explain the 17 PCAs. One more interesting possibility is that one of the PCNA parents achieves non-astringency in a different way than assumed (6 recessive NA alleles), as with the Chinese non-astringent varieties.
- PCA x PCA crosses should produce 100% PCA offspring, unless the PCA parents harbor either (a) at least 3 PCNA alleles each, or (b) at least 1-2 PVNA alleles combined. But then of course if the variety harbors even 1 PVNA allele then it should behave as PVA.
In this study, there were 3 PCA x PCA crosses, producing 60 seedlings of which 56 (93.3%) were classified as PCA. 0 persimmons were unidentified, 1 was identified as PCNA, 1 as PVA and 2 as PVNA. Again, this very high percentage is consistent with expectations – but again it is not 100%. As there were only 3 crosses (6 or fewer parents), it’s difficult to attribute these exceptions to parental genetics. The most likely explanation is classification error.
- PCNA x PVNA crosses make for difficult predictions. If we assume that a PVNA is basically a PCA variety with few or no PCNA alleles and 2 or more PVNA alleles, then PCNA x PVNA crosses should produce a high proportion of PCA offspring, a high proportion of PVNA offspring, some PVA offspring, and a 0 PCNA offspring.
In this study, there were 11 PCNA x PVNA crosses, producing 204 seedlings of which 95 (46.6%) were classified as PVNA, which is consistent with expectation. 6 persimmons were unidentified, 38 (18.6%) were identified as PVA, 58 (28.4) were identified as PCA, and inexplicably 7 (3.4%) were classified as PCNA.
- PVA x PCA crosses also make for difficult predictions. If we assume that a PVA is basically a PCA variety with only 1 PVNA allele, then PVA x PCA crosses should produce a high proportion of PCA offspring, a high proportion of PVA offspring, and 0 PCNA or PVNA offspring.
In this study, there were 3 PVA x PCA crosses, producing 40 seedlings of which 24 (60%) were classified as PCA, which is consistent with expectations. 0 persimmons were unidentified; 0 were identified as PCNA. 10 offspring (25%) were identified as PVA. Unexpectedly, 6 persimmons (15%) were identified as PVNA. It’s very difficult to explain how the PVNA trait could be more concentrated in an offspring than in its parent. The most likely explanation is that it’s just difficult to distinguish PVA from PVNA.
- PCNA x PCA crosses should produce 100% PCA offspring, unless there are PVNA alleles hidden within the PCNA variety.
In this study, 16 PCNA x PCA crosses produced 201 offspring of which 184 (92.0%) were classified as PCA. This is consistent with expectations. There was 1 PCNA (0.5%), evidently a classificatiuon error. There were 7 (3.5%) persimmons identified as PVA, 9 (4.5%) identified as PVNA. These classifications are dubious but not impossible. In any case, these results seem strong confirmation of the recessive nature of the PCNA allele – PCNA x PCA crosses should not be expected to produce PCNA offspring.
In sum, these results are somewhat messy but they seem generally consistent with an inference that (1) PCNA varieties have 6 recessive NA alleles, (2) PVA varieties have 1 PVNA allele, (3) PVNA varieties have 2 or more PVNA alleles, and (4) PCA varieties have (a) 0 PVNA alleles but (b) possibly some PCNA alleles.
The results also demonstrate how difficult it can be to classify a variety. PVA and PVNA classifications seem especially frought. Roughly 1% (9/1007) of the PCNA x PCNA offspring were classified PVA or PVNA, which is conceptually impossible. And >5% (3/60) of the PCA x PCA offspring were classified PVA or PVNA, which seems genetically impossible. Human error is the most likely explanation.
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From what I’ve seen, a single seed is all you need to distinguish a PVNA variety from a PC since the flesh immediately around the seed changes color. Not sure if this applies to PVA varieties too.
Because of this, I am skeptical of lumping the results from crosses between multiple cultivars the way this paper did. We wouldn’t expect the progeny segregation for a PCNA crossed to a PCA cultivar with 5 PCNA alleles to be the same as that PCNA crossed to a PCA with no PCNA alleles. So it doesn’t make sense to consider them all together as a PCNA x PCA category. And breaking them down to individual crosses doesn’t really give you enough progeny for any one cross to have statistically significant numbers.
If this were the case, there should be a higher percentage of non-PCNA progeny, since all progeny of that cultivar would be non-PCNA unless crossed with another cultivar with the same mutation, which would be unlikely. This is assuming that the parents were used an equal number of times in the 61 crosses, but since we don’t have a breakdown of the individual crosses, we can’t say.
Thanks for the comments. I don’t think this one is correct. If a gene variant is dominant, it only has to appear in one place. For example, the Chinese NA mutation is dominant, so a C-PCNA x PCA cross produces ~ 1/6 C-PCNA offspring.
Well, for sure one seed is not enough to distinguish PVA from PVNA. All you’d know is whether there’s some degree of PV.
Also, color change seems not to be perfectly correlated with astringency loss. A seeded Fuyu shows color change but there’s no significant astringency before or after. Bottom line, getting some PV (color change) isn’t a certain indicator of A or NA, especially if there’s only one seed.
If a different PCNA mutation exists in Japanese persimmon cultivars, it would most likely be recessive as well, given the relative lack of PCNA cultivars despite a few centuries of selection. And since it would also likely be a mutation in a different part of the biosynthetic pathway, the two would complement and you would get the wild-type astringent fruit.
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Does anyone here cover their persimmon grafts for a few weeks after doing them?
I wrap my scions and graft in parafilm. It’s easiest to prewrap the scions beforehand (I do it when initially storing them). Then you just nip off the end, unwrap where your cut will be, make your cuts, and wrap the graft union with whatever (I use a rubberband) and then a layer of parafilm over the union until it overlaps with the parafilm on the scion. Pretty simple, I never have to worry about my scions drying out, and it’s very very rare for me to lose a new persimmon graft. Seems a lot easier than bagging a graft and such.
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Yeah, that make sense. I guess “human error” pops to the top of the list of possible explanations of PCNA x PCNA offspring as anything other than PCNA.
Thanks Andrew, I meant after you do the grafts do you cover them with foil wrap or envelopes to protect from rain or sun? With figs I normally do that if hotter than 85°f and going to rain.