rose ploidy

I was wondering, what is the best place to find out information on the ploidy of the roses that we want to work with?

I was wondering, what is the best place to find out information on the ploidy of the roses that we want to work with? I have made a number of crosses using old blush with other hybrid teas. I remember reading that old blush is in the background of almost all modern roses. Recently I read that it was diploid and that most HBTs are tetraploid. This being the case, how can it be that old blush is present in all of them? The hips on my plant are developing beautifully, but will my seedlings all suffer from fertility problems?