Take human genetics for example, eye color to be more specific. I think the strength of human eye color goes like this from weakest to strongest as from lightness to darkest color. Say a blue eyed person marries a brown eyed person and they have kids, the likeliness of them having blue eyed kids is less then brown, and on down the line it would continue, brown eye, after brown eye, till all the sudden a blue eye will show up.... The same would be said for green and blue, blue overpowers green.

But that to be said coloring has other advantages and disadvantages. As much for human eyes as for guppies tales I'm sure...

So in short if your mating guppies are true strains then you may get a little of both.. The males more likely to take on the coloring then the females. But if there not true strains then you never know what you might get.... A living breathing breading surprise bag..

Oh and can you be sure that she hasn't already been pregnant as stated many times a guppy can hold what she needs to have fry for quite a long time for many different batches, for perhaps many different males.... So with breading its kind of iffy unless you know the fishs history, either through the original breeder, or by breeding out the guppy alone till she is empty and then experimenting with different males to see where each color change comes from..