You might have some work to get them to breed true. At first that male will influence the offspring's color, but there will be variation because of the genetics coming from the female. Even good strains still throw occasional variants, and part of the work is removing those from the gene pool. To maintain vigor you would have to work at least two, three or four would be better, separate lines of the same color morph and after a number of generations cross the lines to maintain vigor. Each time you'd do several crosses so you'd end up with as many lines as you started with.