Look at the difference in form from early flowers until the present day. There are whites in the mix (Cup Race) for example--if you cross blues & white it will eventually come out blue. For a difficult trait, hybridizers may self & sometimes do siblings if they can't find the trait anywhere else. Marty Schaffer when he started Siberians did sibling crosses. Now he has spread some of the colors around so he doesn't have to do so. It is easier with flowers--mistakes can go to the compost pile. With dogs you must find a good home if the trait doesn't turn out the way that you wish.
