Question

A Dihybrid cross is done between two parent pea plants (pure line) who differ in two pairs of contrasting traits: Seed colour and seed shape.

In the F₂ generation the number of phenotypes and genotypes will be:

Options

• phenotypes = 4; genotypes = 16

• phenotypes = 9; genotypes = 14

• phenotypes = 4; genotypes = 8

• phenotypes = 4; genotypes = 9

Answer 1

phenotypes = 4; genotypes = 9

Explanation:

In the F₂ generation, a dihybrid cross has a 1 : 2 : 1 : 2 : 4 : 1 : 2 : 2 : 1 genotypic ratio and a 9 : 3 : 3 : 1 phenotypic ratio, which means there are:

4 phenotypes (different physical traits)

9 genotypes (genetic combinations)