Question

A homozygous tall plant (TT) of Mirabilis jalapa was crossed with its bred true dwarf plant (tt) giving F1 Tall plants. However, the dwarf plants reappeared in F2. Cross out these plants and show the proportions of the Tall to the dwarf plants in the F2.

Answer 1

1 Dwarf (tt) plant

Step-by-step explanation:

The cross used to generate the F1 and F2 plants is as follows:

TT (Homozygous Tall Plant) x tt (Bred True Dwarf Plant)

The F1 generation of plants would all be Tall (Tt) as this is a monohybrid cross.

For the F2 generation, the plants would be segregated in a 3:1 ratio of Tall to Dwarf plants. There would be three Tall (Tt) plants for every one Dwarf (tt) plant. The cross would look like this:

Tt (F1 Tall Plant) x Tt (F1 Tall Plant)

The F2 generation of plants would be made up of the following:

3 Tall (Tt) plants

1 Dwarf (tt) plant