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05/12/2021 4:35 pm
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Define and design a test-cross.
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05/12/2021 4:38 pm
The crossing of F1 individuals having dominant phenotype with its homozygous recessive parent is called test cross. The test cross is used to determine whether the individuals exhibiting dominant character are homozygous or heterozygous.
Example: When a tall plant (TT) is crossed with the dwarf plant (tt) in the F1, generation only tall plant (Tt) appears which is then crossed with homozygous recessive (tt) in a test cross.
In the given test cross between tall heterozygous F1 hybrid with dwarf homozygous recessive parent produces tall and dwarf progeny in equal proportion indicating that F : hybrids are heterozygous.