Makes sense. Yeah, it'll be really interesting to see how those hybrids turn out and if they'll handle Wahl's climate. I'm kinda wondering if I should get a Prague now. I've held off on it since I didn't see much breeding value in them, and I can grow regular satsumas without too much protection here. But I'm not aware of many satsumas that can be used as parents (even as pollen parents, since a lot of satsumas are nearly sterile) given the low seededness, poor vigor, and them being highly nucellar. If it turns out Prague is reliably producing zygotic seed with satsuma as the female parent, that's really useful!
I guess it depends on how long you plan on living, haha. Man, zone 6b is a tough one. Are there even any 50/50 trifoliate hybrids that survive 6b, I'd have thought you'd need an F2 or backcross to trifoliate to get that kind of cold tolerance? Still, totally doable, it'll just take a while. But there's been such an explosion of breeding work and available material in the last few years. We've got Kim Bowman releasing all these new hybrid rootstocks, many of which should be quite useful for breeding, we've got kumin and his massive trial, we've got Ilya and others in Europe doing their thing (if a bit slower given their higher latitude and shorter, cooler summers), and all the numerous others who are working on new crosses.
I can't imagine we're more than a decade or two away from some pretty significant results in cold hardy citrus, both in terms of zone 8 hardy commercial-quality citruses and zone 7 or maybe 6 hardy palatable citrus.
