Question

Read the following and answer from given below:

Prashant wanted to find the genotype of a pea plant bearing purple coloured flowers in his kitchen garden. For this, he crossed purple-flowered plants with white-flowered plants. As a result, all plants which were produced had purple flowers only. Upon selfing these plants, 75 purple flower plants and 25 white flowers plants were produced. Now, he can determine the genotype of a purple-flowered plant by crossing it with a white-flowered plant.

In white-flowered plants, the allele is expressed in ______ 

Options

• heterozygous condition only

• homozygous condition only

• F₃ generation

• both homozygous and heterozygous conditions.

Answer 1

In white-flowered plants, the allele is expressed in homozygous conditions only.

Explanation:

The factor of an allelic or allelomorphic pair that is unable to express its effect in the presence of its contrasting factor in a heterozygote is called recessive factor or allele, e.g., the allele 't' in hybrid tall pea plant Tt. The effect of recessive factor becomes known only when it is present in the pure or homozygous state, e.g., tt in dwarf pea plant.