Question

You are asked to find the genotype of a pea plant bearing violet flowers, growing in your school garden. Give your explanation to get the solution.

Answer 1

A test cross is performed to determine the genotype of a violet flower-bearing plant (dominant trait). The plant with violet flowers (unknown genotype – VV or Vv) is crossed with a homozygous recessive white flower plant (vv).

1. If the violet plant is homozygous dominant (VV):
   VV × vv → All offspring will be Vv (violet flowers).
   This shows the parent is homozygous dominant.
2. If the violet plant is heterozygous (Vv):
   Vv × vv → Offspring will be 50% Vv (violet) and 50% vv (white).
   This shows the parent is heterozygous.

Thus, a test cross helps determine whether the dominant parent is homozygous or heterozygous.