In peas, purple flowers (P) are dominant to white flowers (p), and tall plants (T) are dominant to short plants (t). A short plant with white flowers would have the genotype

In the question, it is given that the purple flowers are dominant to the white flowers and the tall plants are dominant over the short plants. The dominant allele for the flower is P, and the recessive allele for the flower is p. The dominant trait for the height is T, and the recessive trait is t.

So, the possible genotypes of the purple flower is - PP or Pp.

And, the possible genotype of the white flower is - pp.

The possible genotypes of the tall plant is - TT or Tt.

The possible genotype of the short plant is - tt.

Hence, the genotype of a short plant having white flowers would be pptt, representing all the recessive traits.