How could the botanist best determine whether the genotype of the green-pod plant is homozygous or heterozygous?

how could the botanist best determine whether the genotype of the green-pod plant is homozygous or heterozygous?

To determine whether the genotype of a character with the dominant phenotype is homozygous or heterozygous, crossing the same character with a homozygous recessive trait is called a “control cross.”

can use yellow bean plant for control cross