Final answer:
It is easier to deduce the genotype in cases of complete dominance, as the recessive phenotype clearly indicates a homozygous recessive genotype, whereas the dominant phenotype does not distinguish between homozygous and heterozygous genotypes. Incomplete dominance allows for direct genotype deduction from the intermediate phenotype.
Step-by-step explanation:
It is easier to deduce the genotype of organisms for an allele that exhibits complete dominance compared to incomplete dominance. This is because, in cases of complete dominance, the presence of the dominant phenotype indicates at least one dominant allele, but the homozygous recessive genotype will only show the recessive phenotype. However, with incomplete dominance, heterozygous organisms exhibit an intermediate phenotype, which is distinct from both homozygous forms, allowing us to infer the genotype directly from the phenotype.
For instance, if we consider flower color in peas with complete dominance, purple-flowered peas could be homozygous dominant (PP) or heterozygous (Pp), but white-flowered peas can only be homozygous recessive (pp), making the recessive genotype clear but rendering the dominant genotype ambiguous without further testing. In contrast, with incomplete dominance, as seen in snapdragons, the intermediate pink color (CRCW) is indicative of a heterozygous genotype, enabling us to deduce the genotype without ambiguity.