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A cross in which an organism showing a dominant phenotype is crossed with the recessive parent in order to know its genotype is called
A
Monohybrid cross
B
Back cross
C
Test cross
D
Dihybrid cross
Detailed Solution
An organism with the dominant phenotype may be homozygous dominant or heterozygous.
To find out which, it is crossed with the homozygous recessive parent; this is a test cross.
If all the progeny show the dominant trait the organism is homozygous ($TT \times tt$); if dominant and recessive appear in a 1 : 1 ratio it is heterozygous ($Tt \times tt$).
A back cross is the cross of an $F_1$ individual with either of its parents (dominant or recessive); the test cross is the particular back cross with the recessive parent, done to know the genotype.
Hence the cross is called a test cross.
To find out which, it is crossed with the homozygous recessive parent; this is a test cross.
If all the progeny show the dominant trait the organism is homozygous ($TT \times tt$); if dominant and recessive appear in a 1 : 1 ratio it is heterozygous ($Tt \times tt$).
A back cross is the cross of an $F_1$ individual with either of its parents (dominant or recessive); the test cross is the particular back cross with the recessive parent, done to know the genotype.
Hence the cross is called a test cross.