You may find this article os interest concerning rose genes.
Dr. David Weiss came and gave a seminar here at the University of Minnesota last year on this work. It was interesting indeed. It sounded like there are so many genes that it will be very unlikely to have a simple approach to introduce fragrance in a non-fragrant variety with a single, or even a few, genes. Each rose has its own profile for all these chemicals and fragrances we find pleasing rely somewhat on relative concentrations of these various compounds. It’s great that this research is being done. Even if finding a practical application for this information will take awhile, it is just valuable to learn and understand more about fragrance.
One thing I hold for sure since years:
Life is no “Meccano”, we cannot think “linearly”
like with machines, say, rose A is “disease-resistant”
(whatever this may mean), rose B is fragrant so I marry
them and got the jackpot…It definitely don’t work
that way, and the more we shall know about it, the more
we shall realize it’s too complicated for us to play with.
I believe the great breeders where, and are, artists above anything else -be they at work “scientifically” or not-.