A plant breeder is trying to develop a deep purple violet. She knows the purple violets she has can be PP or Pp for the purple color. She crosses two purple violets hoping to produce a deeper color. Under what circumstances can she be sure that the resulting offspring will all be purple?

a. Both parents must be PP. -------Incorrect
b. Both parents must be Pp.
c. At least one parent must be Pp.
d. At least one parent must be PP.

I thought it was A. Both parents must be PP, but it was incorrect? Can someone help me find the correct answer and why it is the correct answer.

The alleles representing the purple violet color be represented by "P" and it is easy to understand from the given facts that "P" is dominant over "p"

There fore both homozygous gamete "PP" and and heterozygous gamete"Pp" represents the deeper purple color.

In order to have all the offspring of purple color , at least one of the parents must have PP genotype.

Let us say if one parent is for sure having"PP " genotype and other parent be any of the three i.e PP, Pp, pp genotypes are crossed together , then all the offspring will be purple in color.

Hence, option D is correct