Question

What is the genotype of a plant showing a dominant phenotype of violet flowers if it is test crossed and produces both violet-flowered and white-flowered plants?

(a) VV

(b) Vv

(c) vv

(d) v

This question was addressed to me at a job interview.

I want to ask this question from Inheritance Principles topic in section Principles of Inheritance and Variation of Biology – Class 12

Answer 1

Right choice is (b) Vv

Easiest explanation: If a cross occurs between violet-flowered and white-flowered plants, the offsprings will have an allele v. To have both violet and white flowers, the violet-flowered parent should be able to produce both V and v containing gametes. Thus, the genotype of the unknown parent will be Vv.