Write down the possible genotypes, as determined by the phenotype.
a. if the phenotype is that of the dominant trait (for example, purple flowers), then the genotype is either homozygous dominant or heterozygous (pp or pp in this example).
b. if the phenotype is that of the recessive trait, the genotype must be homozygous recessive (for example, pp).
c. if the problem says "true-breeding," the genotype is homozygous.

a. If the phenotype is that of the dominant trait (for example, purple flowers), then the genotype is either homozygous dominant or heterozygous (PP or Pp in this example).

To draw the genotype here, you have two possible options: PP homozygous dominant or Pp heterozygous dominant.

b. If the phenotype is that of the recessive trait, the genotype must be homozygous recessive (for example, pp).

Yes, in this case, if you want a recessive trait to show on the phenotype your only option is to have pp alleles.

c. If the problem says "true-breeding," the genotype is homozygous.

In this case, your only option is P or p.

Either if it's dominant ( capital letter) or recessive (lower letter)