Question

A cross is carried out between two pea plants. One of the pea plants is tall and has yellow-colored seeds, and the other pea plant is short and has green-colored seeds. All of the offspring obtained from the cross are tall and have yellow-colored seeds. Which combination represents the dominant traits from the cross of the pea plants?

Answer 1

Since all of the offspring are tall with yellow seeds, tall and yellow are dominant.  This suggests the the genotype of the tall and yellow plant is TTYY, and the genotype for the short and green plant is ttyy.  In a cross between the two plants, each parent gives one allele for each gene.  Since each parent only has one type of allele, all of the offspring are heterozygous for both traits, or TtYy.