Question

Assuming that both parent plants in the diagram below are homozygous, why would all of the F₁ generation have yellow phenotypes?

Answer 1

According to Mendel's Law of Dominance, the allele determining yellow seed colour is completely dominant over the allele determining green seed colour. In the hybrid F₁ generation, all offspring carry a heterozygous pair of alleles (Yy), where the dominant yellow trait completely masks and suppresses the expression of the recessive green trait.