Final answer:
The parental genotypes in a test cross can be represented using the dash technique for unknown genes.
Step-by-step explanation:
The parental genotypes in a test cross can be represented using the dash technique for unknown genes. For example, let's say the father has the genotype SSrr and the mother has the genotype ssRR. Using dashes for the unknown genes, we can represent the cross as S-rr x ssRR.