In peas, the smooth allele is dominant over the wrinkled allele. A plant with round peas was crossed to a plant with wrinkled peas and all of the resulting plants had smooth peas. What are the genotypes of the parents in this cross?
A) Rr × Rr
B) rr × rr
C) RR × Rr
D) Rr × rr
E) RR × rr

Question

Quizplus · Accepted Answer

Since all offspring have smooth peas, one parent must have two dominant alleles (RR) and the other must be homozygous recessive (rr) to only pass on the wrinkled allele.

In Peas, the Smooth Allele Is Dominant Over the Wrinkled