Heterozygous tall and violent flower garden pea plants were selfed, and total 1200 plants are collected. What will be the total number of plants with first dominant and second recessive traits?

Options

A. 150
B. 675
C. 225
D. 450

Answer

To solve the problem, we need to determine the number of plants that exhibit the first dominant trait (tall) and the second recessive trait (white flowers) after selfing heterozygous tall and violet flower garden pea plants.

### Step-by-Step Solution:

1. **Identify the Traits**:
- Tall (T) is dominant over dwarf (t).
- Violet (V) is dominant over white (v).
- The heterozygous tall and violet flower plants can be represented as TtVv.

2. **Determine the Gametes**:
- When TtVv plants are selfed, they can produce four types of gametes: TV, Tv, tV, and tv.

3. **Set Up the Punnett Square**:
- The Punnett square for a dihybrid cross (TtVv x TtVv) will have 16 squares (4x4).
- The phenotypic ratio from this cross is 9:3:3:1.
- 9 plants will be tall and violet (T_V_)
- 3 plants will be tall and white (T_vv)
- 3 plants will be dwarf and violet (ttV_)
- 1 plant will be dwarf and white (ttvv)

4. **Calculate the Total Plants**:
- We have a total of 1200 plants.

5. **Determine the Number of Plants with Dominant and Recessive Traits**:
- The ratio of plants that are tall (dominant) and white (recessive) is 3 out of 16 (T_vv).
- To find the number of such plants, we calculate:
\[ \text{Number of TtVv plants with T and vv} = \frac{3}{16} \times 1200 \]

6. **Perform the Calculation**:
\[ \frac{3}{16} \times 1200 = 225 \]

### Conclusion:
The total number of plants with the first dominant trait (tall) and the second recessive trait (white flowers) is **225**.

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