Joe wrote: “Now what we need is some hardy yellow that’s also seed fertile. It would be fun to cross this hybrid with Hazeldean, for instance.”
That WOULD be nice! That generic rugosa itself accepted ‘Hazeldean’ pollen well. I still have a seedling from that cross - it’s pale apricot/yellow, single and seems to be just as infertile as the rugosa x xanthina.
Adam wrote: “I was surprise you got a yellow even if it is light yellow in a first generation cross with a rugosa. I was expecting something more pink when I clicked on it.”
I think that many of the related Pimpinellifoliae species have some dominant reduction of anthocyanins in the petals. Using that same generic rugosa (with pretty intensely pigmented fuschia/magenta petals), here’s what I’ve gotten in crosses:
rugosa x xanthina - all seedlings pale yellow sometimes with slight pink blush while in bud
rugosa x ‘Hazeldean’ - one seedling - pale yellow/apricot
rugosa x spinosissima - lots of seedlings ranging from stark white to shell pink
rugosa x ‘Double White’ (Scotch rose) - pale pink to medium pink
Betsy wrote: “Your hybrid was the inspiration for me to also try crossing Rugosa and Xanthina, though nothing I’ve gotten so far measures up to yours. My crosses have all been with Rugosas as the seed parents, and Xanthina does seem to put a strong stamp on its offspring through the pollen. They also sucker (Rugosa) and get canker (Xanthina). Can you enlarge a little on the remark you made in your blog about Hurst septet theories for someone who doesn’t know anything about them :^) ?”
I’m glad that I might be encouraging people to play around with more species crosses like this. I wonder if your being too critical of what you’ve gotten so far. I’d bet that they’re every bit as good as my seedlings (which sucker and canker also). As for Hurst’s septet theories… here’s a piece quoted from this page on “Creative Evolution” that sort of fits what I was thinking.
“…we see an illustration of this in the tetraploid species Rosa spinosissima L. found on the sand dunes of Western Europe. This rose is tetraploid in its chromosomes (28) and an analysis of its taxonomic characters shows that it is composed of the characters of two distinct diploid species represented in the figure by the two Linnean species R. rugosa Thunb. and R. Willmottiae Hemsl., each of which has 14 chromosomes. The figure shows that the tetraploid species R. spinosissima combines the tortuous, excessively prickly branches of rugosa with the singly set flowers and small leaflets of Willmottiae, and so on with the other specific characters. Genetical experiments at Cambridge confirm the taxonomic analyses in so far as hybrids between similar Linnean species to the two above present the salient taxonomic characters of R. spinosissima.”
Aside from that “Creative Evolution” link above the quote, you can read lots more at Karl King’s webpage with links to Hurst’s articles.
You can just skip to this Septet Formulae (Table) once you have the basic idea.
Pierre wrote: “Like Betsy I did cross rugosa x bracteata derived seedlings with various pimpinellifoliae pollen. Got a few dozens very nice strong once blooming from pale yellow to red. To date none able to set a hip or pollen progeny.”
Wow Pierre! Rugosa, bracteata and pimpinellifoliae all combined - that’s really cool! You need to start getting pictures for us. I’m not surprised that you’re having infertility issues with them though. I wonder if you could double the chromosome number and gain fertility that way?
Thanks all for your interest!!!