Define test cross. Explain it with an example.

Explanation

Test cross is defined as a cross between an individual of unknown genotype with a homozygous recessive.
In `F_(1)` generation of Mendel.s monohybrid cross of tall and dwarf pea plants, he got only tall plants were in the ratio 3:1. He self-pollinated the dwarf `F_(2)` plants and he got only dwarf plants in `F_(3)` and `F_(4)` generation so he concluded that the genotype of dwarf plant ws homozygous recessive (tt). But the genotype of tall plants TT or Tt cannot be predicted. Mendel crossed the tall plants of `F_(2)` with homozygous recessive dwarf plant. This is known as test cross. From the progenies of the test cross, the genotype of tall plants can easily be identified. Thus a typical test cross is to cross an organism showing dominant phenotype is crossed with the recessive parent instead of self-crossing. Therefore test cross can be used to identify whether an indivdidual is homozygous or heterozygous for dominant character.