Using triploids to create diploids

Studying the history of floribunda and miniature roses, it seems that hybridizers have crossed diploids and tetraploids, and then crossed the resulting triploids with tetraploids (when fertile enough). However, I haven’t found any records where someone took the triploid and crossed it back to a diploid. Are there any known roses that are the result of a diploid x triploid cross?

I think ‘The Fawn’ is maybe a diploid from a triploid. It is a result from ‘The Fairy’ X ‘New Dawn’. Even ‘The Fairy’ itself is a diploid resulting from a cross between a diploid and a triploid as it is a cross between ‘Paul Crampel’ X ‘Lady Gay’. And I think many of the hybrid musks may be diploids from triploids, but they are so weird as a group. Many of them are fertile even when their parentage suggests that they are not soppose to be.

There is a research group headed by Dr. Debener that is doing some inheritance and molecular genetics work in roses. Off the top of my head I think they are in Germany. They have been working with a population of diploid roses that they obtained from open-pollinated triploids that are the result of crossing diploid R. multiflora with tetraploid modern roses.