Question

The phenotypic ratio for the F2 generation in a dihybrid cross will theoretically be _____.

A) 9:3:3:1
B) 1:1:1:1
C) 3:1:1:3

Answer 1

A

Step-by-step explanation:

Answer 2

A) 9:3:3:1

Step-by-step explanation:

Lets consider a true breeding white squash (WWYY) is crossed with a true breeding green squash (wwyy) giving rise to a dihybrid offspring WwYy.

First, let determine the F1 offspring.

If WWYY self crsossed we have: WY, WY as the traits required for the F1 cross,

On the other hand wwyy = wy, wy

Therefore, If a true breeding white squash WWYY crossed with true breeding green squash wwyy, we have the following as the F1 offspring.

WY WY

wy WwYy WwYy

wy WwYy WwYy

Now for the F2 offspring. we will have a dihybrid cross between WwYy * WwYy

WY Wy wY wy

WY WWYY WWYy WwYY WwYy

Wy WWYy WWyy WwYy Wwyy

wY WwYY WwYy wwYY wwYy

wy WwYy Wwyy wwYy wwyy

∴ From the above cross, the phenotypic ratio = 9:3:3:1

9 (WWYY WWYy WwYY WwYy WWYy WwYy WwYY WwYy WwYy)

3 (WWyy Wwyy Wwyy)

3 (wwYY wwYy wwYy)

1 (wwyy)