Question

A red flower of Antirrhinum was crossed with a white flower and pink flowers were obtained in the F₁ generation. When the pink flowers obtained in the F₁ generation were selfed red, white, and pink flowers were obtained in the F₂ generation. Which of the following statements is incorrect?

• A. The law of dominance is not followed in this experiment.
• B. The pink color in the F₁ generation is caused by incomplete dominance.
• C. F₂ has a ratio of 1/4 (Red): 2/4 (Pink): 1/4. (White).
• D. In this experiment, the law of segregation does not apply.

Answer 1

The correct option is D

In this experiment, the law of segregation does not apply.

Figure showing the cross between a red flower of Antirrhinum with a white flower and selfing of pink flowers of F₁.

The correct option is D.

Explanation for the correct option:

The Law of segregation is followed here since during gamete formation each gamete has received one copy of the gene. Hence it is the incorrect statement.

Explanation for the incorrect option:

Option A

1. Because the dominant allele R in pink flowers has not been able to fully express itself, the law of dominance is not obeyed in this experiment.
2. R allele is for red which is incompletely dominant over white colour allele r and hence heterozygous Rr gives half pigment has hence pink flowers are observed.

Option B

1. The pink colour of flowers in the F1 generation is caused by incomplete dominance.
2. The R allele for red is incompletely dominant over white color allele r and hence heterozygous Rr flowers have pink colour.

Option C

1. When pink flowers of F₁ were selfed the F₂ had 1 red flower, 2 pink flowers, and 1 white flower.
2. Therefore, a ratio of 1/4 (Red): 2/4 (Pink): 1/4. (White) is observed.