Question

If in a garden pea plant, a cross is made between red-flowered (RR) and white-flowered (rr) plants. What will be the phenotypic ratio in F${}_2$ generation?

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

Answer 1

Answer: (C)

3 : 1

RR (Red flower) X rr (White flower) $\to$ Rr (F${}_1$ generation)
Selfing of F${}_1$ gives following F${}_2$ generation:

	R	r
R	RR (Red)	Rr (Red)
r	Rr (Red)	rr (White)

The offspring are: 1 RR - Homozygous red-flowered plants
2 Rr - Heterozygous red-flowered plants
1 rr - Homozygous white-flowered plant
Thus, the phenotypic ratio in F${}_2$ generation is 3 red : 1 white.

So, the correction option is 'C'.