When yellow round heterozygous pea plants are self fertilised, the frequency of occurrence of RrYY genotype among the offspring is

Options

A. `9//16`
B. `3//16`
C. `2//16`
D. `1//16`

Answer

To solve the question regarding the frequency of occurrence of the RrYY genotype among the offspring of yellow round heterozygous pea plants, we can follow these steps:

### Step 1: Understand the Genotypes
- The yellow round pea plants are heterozygous for both traits.
- The dominant traits are yellow (Y) and round (R), while the recessive traits are green (y) and wrinkled (r).
- The genotype of the heterozygous yellow round pea plant is RrYy.

### Step 2: Determine the Gametes
- When these plants self-fertilize, they can produce the following gametes:
- RY (dominant for both traits)
- Ry (dominant for round, recessive for color)
- rY (recessive for round, dominant for color)
- ry (recessive for both traits)

### Step 3: Set Up a Punnett Square
- We will create a Punnett square using the gametes from both parents (RrYy x RrYy):

| | RY | Ry | rY | ry |
|-------|--------|--------|--------|--------|
| **RY** | RRY Y | RRYy | RrYY | RrYy |
| **Ry** | RRYy | RRyy | RrYy | Rryy |
| **rY** | RrYY | RrYy | rrYY | rrYy |
| **ry** | RrYy | Rryy | rrYy | rryy |

### Step 4: Count the Genotypes
- From the Punnett square, we can count the occurrences of the RrYY genotype:
- RrYY appears **2 times** in the 16 possible combinations.

### Step 5: Calculate Frequency
- The frequency of the RrYY genotype among the offspring is calculated as:
\[ \text{Frequency} = \frac{\text{Number of RrYY genotypes}}{\text{Total number of offspring}} = \frac{2}{16} = \frac{1}{8} \]

### Conclusion
- The frequency of occurrence of the RrYY genotype among the offspring is **2 out of 16**, which simplifies to **1/8**.