TEST CROSS

Crossing of F hybrid with its homozygous recessive parent is called test cross and the progeny of test cross is called test cross progeny.

A .      Monohybrid Test Cross

Thus monohybrid test cross ratio = 1 : 1

B .      Dihybrid Test Cross

So dihybrid test cross ratio = 1 : 1 : 1 : 1

C.      Trihybrid Test Cross

It involves crossing of a trihybrid (Rr Yy Cc) with triple recessive (rr yy cc). The eight different phenotypes will be obtained in 1 : 1 : 1 : 1 : 1 : 1 : 1 : 1 ratio.

Uses of a Test Cross

The test cross reveals the genotype of an organism displaying the dominant phenotype, hence its name.