PUNNETT SQUARE
Create a Punnett Square and
determine the genotypic and
phenotypic ratio of each
monohybrid cross.
Example:
A green pea plant (GG) is being crossed with a green
pea plant (Gg), yellow is the recessive color.
G
G Genotypic ratio: 2GG : 0gg : 2Gg
50%
GG
50%
Gg
GG
G GG
Phenotypic ratio:
4
green
plants
:
0
yellow
plants
Gg
Gg
g
100% green plants
1. Flower Color
purple is dominant (P)
white is recessive (p)
A PP father and a PP mother
2. Seed Color
yellow is dominant (Y)
green is recessive (y)
A yy father and a yy mother
3. Pod Color
green is dominant (G)
yellow is recessive (g)
A Gg father and a GG mother
4. Flower position
along stem is dominant (A)
at tip is recessive (a)
An Aa father and an Aa mother
5. Pod Shape
smooth is dominant (B)
bumpy is recessive (b)
A Bb father and a bb mother