Q. A test cross is carried out to :

Q. A test cross is carried out to :

(a) Determine the genotype of a plant at F2

(b) Predict whether two traits are linked

(c) Assess the number of alleles of a gene

(d) Determine whether two species or varieties will breed successfully

Solution :

Correct option : A When a tall plant from F1 or F2 has TT or Tt composition, its genotype cannot be predicted. Therefore, to determine the genotype of a tall plant at F2, Mendel crossed the tall plant from F2 with a dwarf plant. This, he called a test cross. In a typical test cross, an organism showing a dominant phenotype (and 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. So, the correct answer is ‘ Determine the genotype of a plant at F2