Question

To determine the genotype of a tall plant of $F_2$ generation, Mendel crossed this plant with a dwarf plant. This cross represents a

• A. Test cross
• B. Back cross
• C. Dihybrid cross
• D. Reciprocal cross

Answer 1

Answer: (A)

To determine the genotype of a tall plant of $F_2$ generation, Mendel crossed the tall plant from $F_2$ generation with a dwarf plant. He called this a test cross. In a typical test cross an organism (pea plants) showing a dominant phenotype whose genotype is to be determined is crossed with the recessive parent instead of self-crossing. The progenies of such a cross can easily be analysed to predict the genotype of the test organism. Normal test cross ratio for a monohybrid cross is 1:1 and for a dihybrid cross is 1:1:1:1.

So, the correct answer is 'Test cross'.