Although people like Ralph Moore laid down the essential ground work for the modern mosses, it is still a difficult path to follow. Part of the problem is that you are adding another factor into the equation (all the other desirable traits + mossing) and so selecting for all of the qualities you want means you have even fewer seedlings to pick from. Fortunately there are some plants in my arsenal that makes the job a whole lot easier. Moore's 'Scarlet Moss' is one such rose. Not only does it pass on good mossing, with 'Dortmund' represented twice in its pedigree it readily passes on rich coloring.
The seedling pictured here, 10-05-09 came out of a cross of 'Condoleezza' X ('Sequoia Ruby' X 'Scarlet Moss'). The pollen parent is a short plant with 2.5" very double cherry red blooms and moderate mossing, and is a sibling to my commercially available 'Unconditional Love'. The seed parent,'Condoleezza', a Ralph Moore mossy Floribunda, is a modestly mossed pink flowered shrub that often shows a bit of an orange/yellow center. 'Condoleezza' is one of my best seed setters. You can put any pollen on it and get seeds that germinate easily and soon after sowing.
In this cross I was pleasantly surprised to discover not only some reds and deep pinks among the seedings, but this heavily mossed number that opens to bright, clear yellow semi-double blooms. (Two more photos here) There was also one very strong orange mossed seedling in this group which I will post about at some future date. 10-05-09 is a small shrub, not quite a miniature and not quite a Floribunda, about 2 X 2 feet and very full. It blooms in big clusters in flushes all season.
Last year I stopped deadheading it and it formed seeds readily, so this year I plan on using it in breeding to see what it might do. I'm not entirely satisfied with the size of the plant; I'd rather have a full-sized bush with larger, fuller blooms.