You can breed a line of S1s, but you could also do F1s from the pollen, in fact, I think F1's would be more what Tom Hill was talking about.. male pollen from a proven female, onto a different proven female. That way you can select more confidently, as you can be pretty sure a good number of resulting plants will have traits resembling the parents.
Instead of looking for a male that can do it, you just skip that step.
Instead of looking for a male that can do it, you just skip that step.