When I say that a bird is "breeder quality" I usually mean that overall it is a nice bird, but has one or two little things that would prevent it from making a good show bird.
When matched up to the proper mate (a good match should offset weaknesses in both birds), a true breeder-quality bird will have the potential to produce show quality offspring.
It can be difficult to distinguish between production/pet quality, breeder quality, and show quality unless you are intimately familiar with the breed. The best way to start out is to get breeder birds from a knowledgeable, reputable, trustworthy breeder & showperson who can guide you in pairing them properly.