Question

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

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

Answer 1

The correct option is B Round yellow seeds, round green seeds, wrinkled yellow seeds, and wrinkled green seeds

When RRYY is crossed with rryy, all $F_1$ progeny with RrYy genotype will have round yellow seeds. RrYy will produce gametes as RY, Ry, rY and ry. Thus, the $F_2$ generation will produce offspring as below:

1) Round yellow seeds (9)

2) Round green seeds (3)

3) Wrinkled yellow seeds (3)

4) Wrinkled green seeds (1)

Therefore, option B is the correct answer.