A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the `F_(1)` plant were selfed the resulting genotypeswere in the ratio of

Options

A. `3:1::"Dwarf":"Tall"`
B. `1:2:1::"Tall homozygous" : "Tall homozygous":"Dwarf"`
C. `1:2:1::"Tall heterozygous" : "Tall homozygous" : "Dwarf"`
D. `3:1: : "Tall" : "Dwarf"`

Answer

To solve the question regarding the cross between a tall true breeding garden pea plant and a dwarf true breeding garden pea plant, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Parent Genotypes**:
- The tall true breeding plant is homozygous dominant, represented as **TT**.
- The dwarf true breeding plant is homozygous recessive, represented as **tt**.

2. **Determine the Gametes**:
- The tall plant (TT) can only produce gametes with the allele **T**.
- The dwarf plant (tt) can only produce gametes with the allele **t**.

3. **F1 Generation**:
- When the tall (TT) and dwarf (tt) plants are crossed, all offspring in the F1 generation will be heterozygous **Tt**.
- Therefore, the genotype of the F1 plants is **Tt** (all tall).

4. **Selfing the F1 Generation**:
- When the F1 plants (Tt) are selfed, we perform a cross between two heterozygous plants (Tt x Tt).

5. **Construct a Punnett Square**:
- Create a Punnett square to visualize the possible genotypes of the offspring:
```
T | t
---------------
T | TT | Tt
---------------
t | Tt | tt
```
- The resulting genotypes from the Punnett square are:
- **TT** (1)
- **Tt** (2)
- **tt** (1)

6. **Calculate the Genotypic Ratio**:
- The genotypic ratio of the offspring is:
- 1 TT : 2 Tt : 1 tt
- Therefore, the genotypic ratio is **1:2:1**.

7. **Identify the Phenotypes**:
- The phenotypes corresponding to the genotypes are:
- **TT** and **Tt** both express the tall phenotype.
- **tt** expresses the dwarf phenotype.
- The phenotypic ratio is:
- 3 tall (TT and Tt) : 1 dwarf (tt)
- Therefore, the phenotypic ratio is **3:1**.

8. **Conclusion**:
- The resulting genotypes from selfing the F1 plants are in the ratio of **1:2:1**.

### Final Answer:
The resulting genotypes from the selfing of F1 plants are in the ratio of **1:2:1**.