One of the F1 pea plants with a tall stem and violet flowers

One of the F1 pea plants with a tall stem and violet flowers is test-crossed to produce F2 progeny as follows: 597 plants with tall stems and violet flowers and 203 plants with tall stems and white flowers. What is the genotype of the F1 pea plant?

Solution

TTWw X TTWw

The F1 cross between tall, violet flowered pea plants produce F2 offspring having tall, violet flowers and tall, white flowers in the ratio of 3:1.

The genotype of F1 pea plant is TTWw.