Question

When Mendel crossed true-breeding tall pea plants with true-breeding short pea plants, all the offspring were tall. Then he allowed the first generation tall plants to self-pollinate. What were the ratios of phenotypes he expected in the F2 generation?

Answer 1

A. Because this is a monohybrid cross of pea plants that carry two alleles for plant height, the expected ratio is 3 tall : 1 short.

Step-by-step explanation:

Hope this helps :)

Answer 2

3:1

Step-by-step explanation:

Let the allele for tall plant be T; &

The allele for short plant be t

When Mendel crossed true-breeding tall pea plants(i.e TT) with true-breeding short pea plants(I.e tt); all the offspring were tall.

TT × tt

T T

t Tt Tt

t Tt Tt

we can deduce from the punnet square that the F1 offspring are all heterozygous tall plant.

Now, if the first generation (F1) tall plants are allowed to self-pollinate; we have a cross between Tt and Tt

TT × tt

T t

T TT Tt

t Tt tt

We can see phenotypically that we have 3 tall plant(TT,Tt, Tt) and 1 short plant(tt).

Therefore the ratio of phenotypes he expected in the F2 generation is (3:1)