<< You don’t prove anything. >>
Prove? This is not a courtroom. I’m just making a suggestion as to how we can get to a desired goal. And some warnings about possible dead-ends.
<< For Taishu you mean 3 NA gene… 3 PCNA, 3 PVNA? >>
Sorry, I did not think I had to spell it out. We all know (and have stated here repeatedly) that Taishu is PCNA. So obviously 3 NA genes. Are you just being deliberately difficult?
<< it is better to have more openness and seek the right wood. >>
Yes, that’s why I kept asking you how you managed to acquire the scions that you showed off earlier. You were anything but open. You finally made a revealing comment, then quickly deleted it.
<< You criticize as usual the possibility that Cliff is a PVNA! ok but to draw this conclusion you are going to give us the varieties used by the Russians to create Rosseyanka and thus show us that neither Rosseyanka, nor rossey, nor Rossey f2 are carriers of the PVNA genes.>>
This is the direct route. You know that I have asked forum members for more detail, if they have it, on the varieties used in the Ukrainian breeding program. No one is able to provide any; evidently the details are secret and/or there has been so much open pollination that no one knows what happened. One apparently well-informed comment indicated that as the focus of the program was to develop more cold-hardy varieties, the Russians/Ukrainians used reportedly cold-tolerant PCAs rather than more tender PCNAs.
It is reported that Rosseyanka (F1) is the product of a cross between an unnamed Virginiana x an unnamed Kaki. The DV is apparently a Ukrainian seedling identified as #213. The Kaki is also apparently an unnamed seedling identified as Form 48 and/or Form 185. This Rosseyanka (F1) crossed produced a male that was then back-crossed to DV, producing Rosseynka (F2). It is reported that most further hybrids used a male (F2) that is product of this cross.
So Rosseyanka 1 is 50% Virginiana and 50% Kaki. Rosseyanka 2 is 75% Virginiana and 25% Kaki. Of course, Virginiana has no PVNA genes. The Kaki may. Given available information, I can’t know.
Then there is an indirect route. Rosseyanka 1 & 2 have been used to produce MANY offspring. To my knowledge, none of them has displayed any form of early non-astringency. None of them has displayed consistent pollination-variance of the color of the flesh.
Moreover, my understanding is that David Lavergne produced crosses of various Kakis (Saiyo, Honan Red, Great Wall) x a F2 Rosseyanka male. Any one of these Kakis MIGHT carry a PV gene, increasing the odds that any hypothetical PV genes in Rosseyanka might reveal themselves. Yet none of the offspring is reported to be PVNA.
I believe it’s fair to say that IF Rossyanka carries any PV genes, they should/would have been evident in other offspring. Rosseyanka was selected in 1958, more than 65 years ago. Why did the PV trait wait until now?
None of this is absolute proof. But it seems to stacks the odds against the appearance of a PVNA offspring of a Rosseyanka cross. In this particular case, such an outcome would require (1) the presence of PV genes in Costata, which is PCA not PVA or PVNA; and (2) the presence of PV genes in Rossey 2, which is not impossible but seems very unlikely.