Question

A tall plant (TT) is crossed with a dwarf plant (tt). All $F_1$ plants showed tall phenotype. Which of the following correctly defines a test cross?

• A. $TT\left(F_1\right)\times Tt\left(P\right)$
• B. $Tt\left(F_1\right)\times Tt\left(P\right)$
• C. $tt\left(F_1\right)\times Tt\left(P\right)$
• D. $Tt\left(F_1\right)\times tt\left(P\right)$

Answer 1

The correct option is D $Tt\left(F_1\right)\times tt\left(P\right)$

A test cross is defined as the cross between the unknown genotype of the F1 generation with the double recessive parent (phenotypically).

So, the correct test cross will be: Tt (F1) x tt (recessive parent)

So, the correct answer is 'Option D- Tt (F1) x tt (P)'.