Question

In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the $F_2$ generation of the cross $RRYY\times rryy$?

• A. Only round seeds with green cotyledons
• B. Only wrinkled seeds with yellow cotyledons
• C. Only wrinkled seeds with green cotyledons
• D. Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons

Answer 1

The correct option is D Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons

When a dihybrid cross is made between round yellow (RRYY) and wrinkled green (rryy) seeds, all plants of the F1 generation are with yellow round seeds with a heterozygous genotype of RrYy.
Now the phenotypes of the F2 generation are as follows

Hence, the correct option here is round seeds with yellow cotyledons and wrinkled seeds with yellow cotyledons.