Question

In a dihybrid cross AABB $\times$ aabb, $F_2$ progency of AABB, AABb, AaBB and AaBb accurs in ratio of________

• A. 1: 1 : 1 : 1
• B. 9 : 3 : 3 : 1
• C. 1 : 2 : 2 : 1
• D. 1 : 2 : 2 : 4

Answer 1

The correct option is D

1 : 2 : 2 : 4

In an F1 generation, all the offsprings will be hybrids with the genotype(AaBb). To obtain the F2 generation, F1 offsprings are selfed. The gametes of this cross will be AB, Ab, aB and ab.
The punnet square chart for $F_2$ generation is as follows:

Thus, the ratio of AABB : AABb : AaBb : AaBb is 1 : 2 : 2 :4