High-quality breeding still doesn’t stop there. Once a breeder has crossed a strain and narrowed down a phenotype and finally has the one, they will usually backcross that strain to strengthen its genetics.
Backcrossing is a practice where a breeder will cross-pollinate the new strain with itself or a parent—essentially, inbreeding the strain. This makes the strain more homozygous, and strengthens its genetics and desirable characteristics, and also ensures that those genes continue to pass down from generation to generation.