Question

In a dihybrid cross between two heterozygous pea plants (RrYy × RrYy), what is the phenotypic ratio of the offspring for seed shape and seed color? (R = round, r = wrinkled; Y = yellow, y = green)

• A. 1:1:1:1
• B. 9:3:3:1
• C. 3:1
• D. 1:2:1

Hint:

In a dihybrid cross between two heterozygous parents, the phenotypic ratio is typically 9:3:3:1 if the traits are independently assorting. Memorize this ratio for quick recall, but understand it by considering the independent segregation of each trait.