Question

In Mendel's experiment with garden pea, round seed shape (RR) was dominant over wrinkled seed shape (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What will be the products of the cross RRYY x 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
• E. Only round seeds with yellow cotyledons

Answer 1

The correct option is E Only round seeds with yellow cotyledons

Since, round seed shape (RR) was dominant over wrinkled seed shape (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy), round seed with yellow cotyledon will be expressed in heterogenous dihybrid genotype. Hence, the cross between round seed, yellow cotyledon plant (RRYY) and wrinkled seed, green cotyledon plant (rryy) will produce all round seeds with yellow cotyledon. Thus, option "E" is correct.
Parent generation: RRYY x rryy

Gametes : RY ry Offspring : RrYy