Question

An F1 plant that is homozygous for shortness is crossed with a heterozygous F1 plant. What is the probability that a seed from the cross will produce a tall plant. Use a Punnett square to explain your answer and to compare the probable genetic variations in the F2 plants.

Answer 1

1/2

Step-by-step explanation:

This is a monohybrid cross involving a single gene that specifies height in the pea plant. The allele for Tallness (T) is dominant over the allele for shortness (t).

A homozygous recessive parent will possess (tt) genotype while a heterozygous parent will possess (Tt) genotype. Therefore, in a cross between a Tt and tt (see attached image), a total of four offsprings is possible.

2 of the offsprings will possess a Tt genotype while the other two will possess a tt genotype making the genotypic ratio 1:1.

2 Offsprings Tt will be phenotypically tall while 2 offsprings tt, short. Hence, the probability of having a tall plant from this cross is 2/4 or 1/2.