Biology - Principles of Inheritance and Variation Question with Solution | TestHub

A phenotypic ratio of $3:1$ for tall and dwarf offsprings is obtained in a monohybrid cross when both parents are heterozygous for the trait.

Let the dominant allele for tallness be $T$ and the recessive allele for dwarfness be $t$.

When two heterozygous parents ($Tt$) are crossed ($Tt\times Tt$), the gametes produced by each parent are $T$ and $t$.

The resulting offspring genotypes are $1$ $TT$ : $2$ $Tt$ : $1$ $tt$.

The corresponding phenotypes are $3$ tall ($TT$ and $Tt$) and $1$ dwarf ($tt$).

Thus, the genotypes of the parents must be $Tt$ and $Tt$.

Answer: Tt and Tt