As previously noted in other persimmon threads:
Is a non-astringent American-Asian hybrid persimmon within reach? - #366 by Richard
Dax – Thanks for this summary. As noted elsewhere, I accept your point that much of this isn’t proven. But it is consistent with what we have observed, and hopefully it is close enough to the underlying reality to guide breeding strategy.
Some practical conclusions:
Yes, as you state, the most direct approach to a non-astringent hybrid would be a cross using a C-PCNA parent. According to published research, such intra-specific (Kaki x Kaki) crosses have already produced new non-astringent [pure Kaki] offspring. We’ll just have to wait and see whether interspecific (Kaki x Virginiana) crosses are as successful. As you note, the breeding results suggest that C-PCNA cultivars have 1 or 2 of 6 NA alleles.
A more difficult approach to a non-astringent hybrid is to use J-PCNAs. The difficulty here is assembling the required 6 of 6 NA alleles in one hybrid package. Both intra-specific (PCA Kaki x PNCA Kaki) and inter-specific (PCA Virginiana x PCNA Kaki) require back-crosses to achieve this result. As an example, I’ve suggested that JT-02 should be back-crossed to its male parent, Taishu.
This second approach has the advantage that it is more accessible – some of us (!) have been able to get our hands on Taishu. Or we could use other J-PCNA varieties with male flowers. It seems to me (but this is purely intuitive) that as Taishu is itself a hybrid of PCNA varieties Fuyu, Jiro, Hanagosh and Okugoshu, it may be relatively immune to further hybrid depression whereas adding more Gosho genes may backfire.