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.

To determine the genotype of a purple-flowered plant, Prashant crossed this plant with a white-flowered plant. This cross represents a ______ 

Options

• test cross

• dihybrid cross

• reciprocal cross

• trihybrid cross

Answer 1

To determine the genotype of a purple-flowered plant, Prashant crossed this plant with a white-flowered plant. This cross represents a test cross.

Explanation:

In a test cross, an organism (pea plant) showing a dominant phenotype whose genotype is to be determined is crossed with the recessive parent instead of self-crossing. The progenies of such a cross can easily be analyzed to predict the genotype of the test organism. The normal test cross-ratio for a monohybrid cross is 1 : 1 and for a dihybrid cross is 1 : 1 : 1 : 1.