when a cross is made between pink flower and red flower snap dragon plants, what proportion phenotype in the F_1 offspring could be expected to be red?

Options

A. 0.25
B. 0.75
C. 0.5
D. 0.125

Answer

To solve the question regarding the proportion of red flowers in the F1 offspring when crossing pink and red flower snapdragon plants, we can follow these steps:

### Step 1: Understand the Genetics of Snapdragon Flower Color
Snapdragon flower color exhibits incomplete dominance. This means that when a red flower (dominant) is crossed with a pink flower (intermediate), the resulting offspring will show a blend of the two colors.

### Step 2: Define the Genotypes
- Let’s denote the allele for red flowers as **R** (dominant) and the allele for pink flowers as **r** (recessive).
- The genotype of the red flower is **RR** (homozygous dominant).
- The genotype of the pink flower is **Rr** (heterozygous).

### Step 3: Set Up the Cross
We will cross the red flower (RR) with the pink flower (Rr):
- Red Flower (RR) produces gametes: **R** and **R**
- Pink Flower (Rr) produces gametes: **R** and **r**

### Step 4: Create a Punnett Square
We can create a Punnett square to visualize the possible genotypes of the F1 generation:

```
R R
---------------
R | RR | RR |
---------------
r | Rr | Rr |
---------------
```

### Step 5: Analyze the Offspring Genotypes
From the Punnett square, we can see the following genotypes for the F1 generation:
- 2 offspring with genotype **RR** (red)
- 2 offspring with genotype **Rr** (pink)

### Step 6: Determine the Phenotypic Ratio
Now, we can determine the phenotypic ratio:
- Red flowers (RR) = 2
- Pink flowers (Rr) = 2

This gives us a total of 4 offspring:
- Proportion of red flowers = 2/4 = 0.5
- Proportion of pink flowers = 2/4 = 0.5

### Conclusion
The proportion of red flowers in the F1 offspring is **0.5**.

### Final Answer
The expected proportion of red flowers in the F1 offspring is **0.5** (Option C).