I think it means that homozygous has the same gene on both the maternal and paternal chromosones, and hetero means it has a different gene on each chromosone. this information is useful for breeding. Say you had two homozygous blue (male and female), then all their children would be homozygous blue. If you had two heterozygous blue and we assume the blue is a recessive gene, then a child would have a 1/4 chance of being blue (homozygously) (If its a dominant gene then 3/4 would be blue - 1/2 heterozygous blue, 1/4 homozygous blue).