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 F2 generation of the cross $RRYY\times rryy$?

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

Answer 1

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

Since round seed shape is dominant over wrinkled seed shape and yellow cotyledon is dominant over green cotyledon so RRYY individuals is round yellow and rryy is wrinkled green.

Round yellow seeds X Wrinkled green seeds

$\begin{array}{ccc}RRYY& X& rryy\\ & \downarrow & \\ F_{1}generation& RrYy,& \end{array}$

F2 generation is obtained by selfing F1.


Expected phenotypes in F2 generation are round yellow seed 9, wrinkled yellow seed 3, round green seed 3, wrinkled green seed 1.