Question

In garden peas, green pod color is dominant over yellow pods. Also, round seed shape is dominant over wrinkled seed. Cross-fertilization was done between a pea that is homozygous dominant for pod color with heterozygous round shape and another pea that is heterozygous for both pod color and seed shape. Determine the genotypic ratio and phenotypic ratio of the offspring.

Answer 1

Let the following genes be responsible for different traits:

A - green color;

a - yellow color;

B - round shape;

b - wrinkled form.

The cross will look like this:

AABb × AaBb

↓

Based on the Punnett square, the genotypic and phenotypic ratios respectively will be as follows:

• 2 AABB (highlighted in red) + 4 AABb (highlighted in blue) + 2 AAbb (highlighted in purple) + 2 AaBB (highlighted in yellow) + 4 AaBb (highlighted in green) + 2 Aabb (not highlighted in color, but highlighted in bold)
• 12 green and round (highlighted in gray fill) + 4 green and wrinkled (not highlighted in color fill)