Question -
Answer -
A test-cross can be defined as a cross of an F1 individual that has a dominant phenotype with its homozygous recessive parent. This test cross can be used to determine if an individual displaying dominant character is homozygous or heterozygous.
Sample test cross:
тАв Take a tall plant (TT) and cross it with a dwarf plant(tt)
тАв The F1 generation shows tall plant (Tt)
тАв This tall plant(Tt) is then test crossed with homozygous recessive plant(tt)
As seen above, the test cross between tall heterozygous F1 hybrid with dwarf homozygous recessive parent producing tall and dwarf in the same equal proportion. This represents that the F1 hybrid are heterogenous.