Question

The genotype of green stemmed tomato plants is denoted by GG and that of purple-stemmed tomato plants as gg. When these two plants are crossed:

(a) What color of stem would be expected in their F1 progeny?

(b) Give the percentage of purple-stemmed plants if F1 plants are self-pollinated.

(c) In what ratio would you find the genotype GG and gg in the F2 progeny?

Answer 1

1. When the two plants were crossed in a monohybrid cross, it resulted in the formation of F₁ progeny that was green colored and the genotype is heterozygous dominant (Gg).
2. When F₁ plants are self-pollinated, then out of four plants, three plants are green stemmed (75%) whereas, one plant is purple stemmed (25%).
3. In the F₂ progeny, GG (Homozygous dominant, Gg (heterozygous dominant), and gg (homozygous recessive) were present in a ratio of 1:2:1. Ratio of GG and gg is 1:1.