Subtle? I had thought them intense, considering some like them better than reds. I don’t mind seedy or mealy with brambles (though I’ve yet to taste one with hard large stones). Do the wild ones taste different?
Is Niwot not a particularly great cultivar? OneGreenWorld is selling an everbearing black (which I understand to mean primocane fruiter) called Ohio’s Treasure, and I’m thinking of trying it out. I have Black Hawk (which I think I’ll put into the ground, so I can finally get a crop), and had Allen at the top of my wanted list for quality, according to what I’d read. Considering your experiment, it seems one might breed further primocane fruiters out of pre-existing ones. This bodes well for breeding a higher quality everbearer. Was that large-fruited wild yellowcap a R. occidentalis or was it a R. leucodermis? I did some searching to find out if there was Leuco ancestry in any of the domestic blackcaps, but according to this article, there was only one cultivar reported to be of hybrid descent, and even that one was placed in doubt by the study. According to this one, hybrids between the two tend to inherit inferior traits from the Leuco side (dull colored, soft and smaller fruit). Keep us updated on your hybrid, I might like some stock if it turns out good and you ever have any to spare.
I have very little experience with blackberries. The only ones I recall eating are the Driscoll ones at the supermarket. They’re pretty good! But with all I’ve been reading around this forum lately, I have half a mind to get a dozen varieties to grow for myself, maybe get a taste of that blackberry diversity. Even more so with the everything berries. I understand not all will grow well in my neck of the woods, but I’m willing to try everything that comes my way.
On further searching, I actually managed to turn up some modern information on Rubus nubigenus and a couple of other Andean Blackberries (Rubus subgenus Lampobatus). Apparently fresh consumption of R. nubigenus (a hexaploid species) is limited by its large seeds, but it’s good for processing, with a similar flavor to R. glaucus (the major commercialized species of Lampobatus in South America). Rubus choachiensis is a hard-seeded species mainly used for processing. Rubus robustus is a diploid, and the one that most approaches R. glaucus in quality, with an agreeable acidic flavor and small seeds. I don’t remember where I read this, but I’ve read that R. glaucus is considered on par with the better blackberry hybrids, with a loganberry-like mix of raspberry and blackberry flavor.
The links are in Spanish, so I don’t know how useful they’ll be for the folks here, but I’ll post them for anyone interested:
The main site.
Incidentally, they also have profiles on tropical blueberries, like Vaccinium meridionale, Macleania rupestris and Cavendishia prostrata, as well as other interesting information (other wild fruits, cultivation studies, domestic fruit comparisons, economic potential, etc.).