Two heterozygous red flowers are crossed

Parent genotypes could be Aa x Aa (or whatever letter you'd like to use)

Phenotypic ratio 1 homozygous dominant (red flower) : 2 heterozygous (red flower) : 1 homozygous recessive (white flower)

Genotypic ratio for a heterozygous cross will always be a 1:2:1 ratio