Question

A cross between pea plant with white flowers (vv) and pea plant with violet flowers (VV) resulted in F₂ progeny in which ratio of violet (VV) and white (vv) flowers will be ______.

Options

• 1 : 1

• 3 : 1

• 2 : 1

• 1 : 3

Answer 1

A cross between pea plant with white flowers (vv) and pea plant with violet flowers (VV) resulted in F₂ progeny in which ratio of violet (VV) and white (vv) flowers will be 1 : 1.

Explanation:

A cross between a pea plant with white flowers (vv) and a pea plant with violet flowers (VV) follows Mendelian inheritance.

Step 1: Parent Generation (P)

• White flowered plant = vv (homozygous recessive)

• Violet flowered plant = VV (homozygous dominant)

                                                   VV × vv

Step 2: Formation of F1 Generation

Each parent contributes one allele to the offspring.

• F1 genotype: All offspring will be Vv (heterozygous).

• F1 phenotype: All flowers will be violet because the dominant allele (V) expresses violet color.

F1: 100% Vv (Violet flowers)

Step 3: Formation of F2 Generation (Self-Crossing of F1)

Now, the F1 plants (Vv) are self-crossed:

                             Vv×Vv

Using a Punnett square, the possible combinations in F2 are:

	V	v
V	VV	Vv
v	Vv	vv

Step 4: Genotypic and Phenotypic Ratios

• Genotypic ratio in F2:
  • VV (Homozygous dominant, Violet) = 1
  • Vv (Heterozygous, Violet) = 2
  • vv (Homozygous recessive, White) = 1

• Phenotypic ratio (Violet:White flowers):

  • Violet (VV + Vv) = 3
  • White (vv) = 1

Step 5: Finding the Required Ratio

Since the question specifically asks for the ratio of homozygous violet (VV) to homozygous white (vv), we consider only VV and vv from the genotypic ratio:

VV : vv = 1 : 1

The ratio of homozygous violet (VV) to homozygous white (vv) flowers in the F2 progeny is 1:1.