When a pink flowered Antirrhinum plant is test crossed, then phenotypic ratio in resulting progenies is

Options

A. 1 Red : 1 White
B. 3 Red : 1 White
C. 2 Pink : 1 White
D. 1Pink : 1 White

Answer

To solve the question regarding the phenotypic ratio of the progenies resulting from a test cross of a pink-flowered Antirrhinum plant, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Inheritance Pattern**:
Antirrhinum flowers exhibit incomplete dominance. This means that when a plant is heterozygous (one dominant allele and one recessive allele), the phenotype is an intermediate form rather than showing complete dominance of one trait over the other.

2. **Identify the Genotypes**:
- Let’s denote the dominant allele for red flowers as \( R \) and the recessive allele for white flowers as \( r \).
- The genotype for a pink flower (which is the heterozygous condition) will be \( Rr \).
- The homozygous recessive genotype (white flower) will be \( rr \).

3. **Perform the Test Cross**:
A test cross involves crossing the heterozygous individual (pink flower, \( Rr \)) with a homozygous recessive individual (white flower, \( rr \)).
- The gametes produced by the pink flower (\( Rr \)) will be \( R \) and \( r \).
- The gametes produced by the white flower (\( rr \)) will only be \( r \).

4. **Determine the Offspring Genotypes**:
- The possible combinations from the test cross are:
- \( R \) (from \( Rr \)) and \( r \) (from \( rr \)) → \( Rr \) (pink flower)
- \( r \) (from \( Rr \)) and \( r \) (from \( rr \)) → \( rr \) (white flower)

5. **Count the Phenotypes**:
From the combinations, we have:
- 1 pink flower (\( Rr \))
- 1 white flower (\( rr \))

6. **Calculate the Phenotypic Ratio**:
The phenotypic ratio of the offspring is:
- Pink : White = 1 : 1

### Final Answer:
The phenotypic ratio in the resulting progenies from the test cross of a pink flowered Antirrhinum plant is **1:1** (50% pink flowers and 50% white flowers).

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