A pea plant with a tall stem and violet flowers is crossed w

A pea plant with a tall stem and violet flowers is crossed with a pea plant with a tall stem and white flowers to produce F1 progeny as follows: 597 plants with tall stems and violet flowers and 203 plants with dwarf stems and violet flowers. What are the genotypes of the parents?

Solution

Assume that the gene coding for tall stem is T and the gene coding for dwarf stem is t; T is dominant over t. Similarly, the gene coding for violet flowers is V and the gene coding for white flowers is v; V is dominant over v.

Cross between a tall stem and violet flowers plant heterozygous for tall stem (Tt Vv) and a tall stem and white flowers plant heterozygous for tall stem (Tt vv) will have the progeny with the following genotypes:

Tt VV* Tt vv --à T_ V_ (3/4, tall, violet), tt Vv (1/4, dwarf, violet).

Thus, the genotypes of the parents are, Tt VV and Tt vv.