See:
Very interesting paper. So when I was reading it I noticed two linked genes. One between b-citronellol concentration and double flowers; the other was between b-citronellol concentration and the black spot resistance gene
Rdr1. This seems interesting a least. I have heard that highly scented roses were more prone to black spot but at least in the case their is one scent compound that is linked the other way. The other linked gene b-citronellol concentration and double flowers all this time I thought certain roses smelled better just because they had more petals but maybe I assumed wrong maybe they also have more scent compound per petal also. All I know for sure is I read genetic info like this and half of it goes way beyond my understanding but if I come away with a little bit I am happy. There is a lot of stuff going on down thee rabbit hole. Thanks for the paper.