Question

A pea plant is the F1 offspring of a true-breeding plant with purple flowers and a true-breeding plant with white flowers. This plant is crossed with one that has white flowers (recessive). What percentage of plants in the next generation will likely have white flowers?

Answer 1

Answer: Percentage of 50% of being white.

Explanation: Since white is recessive, it means its allele is w. So, purble must be dominant with allele W.

The parents of the F1 offspring are true-breed, which mean they are homozygous dominant (WW) or homozygous recessive (ww). From this crossing (WW x ww), the F1's genotype is Ww.

This plant is crossed with one with white flower,which means the crossing is between Ww and ww.

From the crossing Ww x ww, we have generation F2 as:

w w

W Ww Ww

w ww ww

Or in other words, we have 2 chances out of 4 of having white, because, since this characteristics is recessive it only shows when the allele is doubled (ww).

So, the percentage of having white is 50%.