Question

A test cross is carried out to

• A. predict whether two traits are linked
• B. assess the number of alleles of a gene
• C. determine the genotype of $F-2$ plant.
• D. Determine whether two species or varieties will breed successfully.

Answer 1

The correct option is A predict whether two traits are linked

When F1 hybrid is crossed with its recessive parent, it is called test cross. By test cross, heterozygosity and homozygosity of the organism can be tested. It gives 1:1 ratio in monohybrid and 1:1:1:1 ratio in dihybrid cross. In presence of linkage the ratio varies from this confirming that the alleles of the genes are not getting segregated randomly according to Mendel's Law.

So the correct option is 'predict whether two traits are linked'.