The term test cross is often used interchangeably with back cross. However two are not necessarily the same. The test cross is a cross of an individual of dominant phenotype to homozygous recessive. On the other hand back cross is mating of an individual of known phenotype to anyone of homozygous parents. For example in above mentioned example the cross between F1 hybrid to homozygous recessive individual is test cross but if we cross the F1 hybrid to a homozygous tall (TT), it is a back cross. Back cross may have special value in some genetic analysis such as Casey incomplete dominance. Because the homozygous necessive individual is also one of the parents, therefore test and back crosses are regarded same.
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