Question

In a cross between red and white-flowered plants of Antirrhinum, all progeny had which coloured flowers?

• A. Pink
• B. White
• C. Red
• D. Equal numbers of red and white

Answer 1

The correct option is A

Pink

The figure shows a cross between red and white-flowered plants of Antirrhinum.

The correct option is A.

Explanation for the correct option:

1. When RR is crossed with rr all progeny has Rr genotype.
2. Since the R allele is incompletely dominant over the r allele Rr genotype has a pink color.
3. Therefore, all the offsprings have pink color flowers.

Explanation for the incorrect option:

Option B

1. Since the genotype of progeny is Rr which gives a pink phenotype.
2. White flowers are produced by the rr genotype.

Option C

1. Since the genotype of progeny is Rr which gives a pink phenotype.
2. Red flowers have the RR genotype.

Option D

1. All progeny have Rr genotype hence, all have pink flowers.
2. It is because the R allele is incompletely dominant over the r allele.