Question

What are the expected phenotypes in $F_2$ generation of cross RRYY $\times$ rryy _______________.

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

Answer 1

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

In a dihybrid cross, a plant with yellow colour round seeds(YYRR) is crossed to green colour wrinkled(yyrr) seeds. In the F1 generation, plant with yellow colour wrinkled seeds(YyRr) are formed. When F1 plant is subjected to self pollination, in the F₂ generation 1YYRR, 2 YYRr, 2YyRR, 4YyRr, 1YYrr, 2Yyrr, 1yyRR, 2yyRr, 1yyrr are formed genotypically and 9 plants are Yellow round, 3 plants are yellow wrinkled, 3 plants are green round and 1 plant is green wrinkled are formed phenotypically.

So, in the F2 generation 4 types of phenotypes appear.

So, the correct option is ‘Four, round seeds with yellow cotyledons, round seeds with green cotyledons, wrinkled seeds with yellow cotyledons, wrinkled seeds with green cotyledons’.