Test cross involves

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4.Principles of Inheritance and Variation

medium

Test cross involves

crossing between two genotypes with dominant trait

crossing between two genotypes with recessive trait

crossing between two $F_1$ hybrids

crossing the $F_1$ hybrid with a double recessive genotype.

(AIPMT-2006)

Solution

(d) : Test cross is performed to determine the genotype of $F_2$ plant. In a typical test cross an organism showing dominant phenotype and whose genotype is to bedetermined is crossed with one that is homozygous recessive for the allele being investigated, instead of selfcrossing. The progenies of such a cross can easily be analysed to predict the genotype of the test organism. Given ahead is an illustration of test cross:

Standard 12

Biology