Round seeds and yellow seed color are dominant to wrinkled seeds and green seed color. Which Punnett square represents the correct way to set up the cross RRYy ´ RrYY? A 4-column Punnett square has 4 rows. The columns are labeled Upper R Upper Y, Upper R y, r Upper Y, r y. The rows are labeled Upper R Upper Y, Upper R y, r Upper y, r y. A 4-column Punnett square has 4 rows. The columns are labeled Upper R Upper Y, Upper R y, r Upper Y, r y. The rows are labeled Upper R Upper Y, Upper R y, Upper R Upper y, Upper R y. A 4-column Punnett square has 4 rows. The columns are labeled Upper R Upper Y, Upper R Upper Y, r Upper Y, r Upper Y. The rows are labeled Upper R Upper Y, Upper R y, Upper R Upper Y, Upper R y. A 4-column Punnett square has 4 rows. The columns are labeled Upper R Upper Y, Upper R Upper Y, r Upper Y, r Upper Y. The rows are labeled Upper R Upper Y, Upper R Upper Y, Upper R Upper Y, Upper R Upper y.

A 4-column Punnett square has 4 rows. The columns are labeled Upper R Upper Y, Upper R Upper Y, r Upper Y, r Upper Y. The rows are labeled Upper R Upper Y, Upper R y, Upper R Upper Y, Upper R y.

Explanation:

This question involves a dihybrid cross i.e. two distinct genes; one coding for seed shape and the other for seed colour. The alleles for round seeds (R) and yellow seeds (Y) are dominant over the alleles for wrinkled seeds (r) and green seeds (y) in the first and second gene respectively.

In a cross between a RRYy and RrYY parent, each will undergo meiosis and produce the following combinations of gametes;

RRYy- RY, Ry, RY and Ry

RrYY- RY, RY, rY, and rY

These gametes will be used to construct a punnet square, which is a square-shaped diagram used to determine the possible genotypes that will be produced by two parents. The punnet square has 4 columns and 4 rows. The four possible gametes of one parent are filled into the four columns and the four possible gametes of the other parent are filled into the four rows (see attached image).

Hence, if the gametes of parent RrYY are filled into the four columns. The columns will labelled:

RY, RY, rY and rY

Also, if the gametes of parent RRYy are filled into the four rows. The rows will be labelled: RY, Ry, RY, and Ry.

This makes the third option correct.