When a heterozygous pea plant with yellow round seeds is crossed with a homozygous pea plant with yellow round seeds, the genotype not obtained is

Options

A. `YyRr`
B. `YyR R`
C. `YYrr`
D. `YYR R`

Answer

To solve the problem of determining which genotype will not be obtained from the cross between a heterozygous pea plant with yellow round seeds and a homozygous pea plant with yellow round seeds, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotypes of the Parents:**
- The heterozygous pea plant with yellow round seeds has the genotype **YyRr** (where Y = yellow, y = green, R = round, r = wrinkled).
- The homozygous pea plant with yellow round seeds has the genotype **YYRR**.

2. **Set Up the Cross:**
- We will set up a Punnett square to visualize the possible combinations of alleles from the cross between **YyRr** and **YYRR**.

3. **Determine the Possible Gametes:**
- The heterozygous parent (YyRr) can produce two types of gametes: **YR** and **yR**.
- The homozygous parent (YYRR) can produce only one type of gamete: **YR**.

4. **Fill in the Punnett Square:**
- The Punnett square will look like this:

| | YR | YR |
|------|------|------|
| YR | YYRR | YYRR |
| yR | YyRR | YyRR |

5. **List the Possible Genotypes:**
- From the Punnett square, we can see the resulting genotypes:
- **YYRR** (from YR x YR)
- **YyRR** (from yR x YR)

6. **Identify the Genotype Not Obtained:**
- The possible genotypes obtained from this cross are **YYRR** and **YyRR**.
- The genotype **YYrr** (homozygous yellow and wrinkled) is not present in the results, as there are no combinations that yield the wrinkled phenotype (rr).

7. **Conclusion:**
- The genotype that will not be obtained from this cross is **YYrr**.

### Final Answer:
The genotype not obtained from the cross is **YYrr**.