Final answer:
The genotype for the locus cannot be completely inferred from the ratio of purple to white flowers in the parents.
Step-by-step explanation:
In Mendel's peas, the genotype for the locus cannot be completely inferred from the ratio of purple to white flowers in the parents. The phenotypes of the offspring, the phenotype of the parents, and the ratio of purple to white flowers in the offspring can all provide information about the possible genotypes at the locus.