Looking at Sunchoke results on search engines I found an article about ‘Genome Skimming’ using the sunchoke. The researchers say that sunchokes must have been recursively hybridized from the Ashy/Hairy Sunflower and the Sawtooth Sunflower. They didn’t explain what they meant by “recursively hybridized”. Anyway I am probably going to obtain a few seeds of both types of sunflowers and see what I get by playing around and cross-pollinating them. If nothing else the flowers will be enjoyable to look at.
Found this article: https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.12560
It does make sense that sunchokes would have developed from two fully perennial parents, rather than from an annual.
We might possibly get a better idea of “recursively hybridized” from studying the extensive annual sunflower breeding work done in Turkey, which would go forward a number of inbred generations before back-crossing? I may be misunderstanding this though:
https://arastirma.tarimorman.gov.tr/ttae/Sayfalar/EN/Detay.aspx?SayfaId=143
In this case, recursive hybridization is just repeated chance crosses and backcrosses between the parent species and their hybrids. I don’t find it surprising that an annual parent was ruled out, because you never see annual progeny out of a sunchoke. If they did have both an annual and perennial parent, then you would expect to see at least the occasional emergence of annual growth habit.
I think it would be very interesting to cross the two putative parents to see what you get. Because you aren’t likely to find much diversity available in these species though, the results will be limited. You might not have access to parents with the right traits.