Question

A Tt plant is crossed with a Tt plant
What percentage of the offspring will be short?

Answer 1

In this case, "T" represents the dominant allele for tallness, and "t" represents the recessive allele for shortness. When you cross two Tt plants, you can use a Punnett square to determine the possible genotypes of the offspring.

The possible combinations of alleles from Tt × Tt are:

- TT (tall)
- Tt (tall)
- Tt (tall)
- tt (short)

So, the resulting genotypes from the cross would be:

- 1 TT
- 2 Tt
- 1 tt

This gives us a total of 4 possible genotype combinations.

Since only the genotype "tt" results in a short plant, we can calculate the percentage of short offspring as follows:

- Number of short offspring (tt) = 1
- Total number of offspring = 4

The percentage of short offspring is:

\[
\text{Percentage of short offspring} = \left(\frac{\text{number of short offspring}}{\text{total number of offspring}}\right) \times 100 = \left(\frac{1}{4}\right) \times 100 = 25\%
\]

Therefore, 25% of the offspring will be short.