In a type of bean plant, the trait for yellow pods (B) is dominant to the trait for green pods (b). A plant that is heterozygous for yellow pods is crossed with a plant that has green pods. An incomplete Punnett square of the cross is shown.

Question

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​Which statement correctly describes the probability that offspring of this cross will display certain traits?
A
75% yellow pods and 25% green pods
B
50% yellow pods and 50% green pods
C
100% green pods
D
100% yellow pods

Answer 1

To determine the probability of the offspring traits, we need to consider the genotypes of the parent plants involved in the cross:

1. The plant that is heterozygous for yellow pods has the genotype Bb (where B represents yellow pods and b represents green pods).
2. The plant with green pods has the genotype bb (since green pods are recessive).

When these two plants are crossed (Bb x bb), we can set up a Punnett square:

        B       b
      ----------------
    b |   Bb   |  bb   |
      ----------------
    b |   Bb   |  bb   |
      ----------------

Now, we analyze the squares:

• The first row produces offspring with genotype Bb (yellow pods).
• The second row produces offspring with genotype bb (green pods).

The resulting genotypes from the cross are:

• 50% Bb (yellow pods)
• 50% bb (green pods)

Therefore, the correct answer is: B: 50% yellow pods and 50% green pods.