Which of the following plant growth regulator breaks dormancy of potato tuber : -

Options

A. Gibberellin
B. IAA
C. ABA
D. Zeatin

Answer

To determine which plant growth regulator breaks the dormancy of potato tubers, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Plant Growth Regulators (PGRs)**:
- Plant growth regulators, also known as phytohormones, are substances that regulate various physiological processes in plants, including growth, development, and dormancy.

2. **Identifying the Role of Gibberellins**:
- Gibberellins are a type of plant growth hormone known for their role in promoting growth and breaking dormancy in seeds and tubers.

3. **Analyzing Other Hormones**:
- Auxins (like NAA - naphthalene acetic acid) are used to prevent sprouting in stored potato tubers, thus maintaining dormancy.
- Indole acetic acid is another auxin but is not specifically used for breaking dormancy in potatoes.
- Abscisic acid (ABA) acts as a stress hormone and helps in closing stomata, which does not relate to breaking dormancy.
- Zeatin is a cytokinin that promotes cell division but does not specifically break dormancy in potato tubers.

4. **Conclusion**:
- Based on the roles of these hormones, gibberellins are the correct choice for breaking the dormancy of potato tubers. Therefore, the answer is **Gibberellins**.

### Final Answer:
The plant growth regulator that breaks the dormancy of potato tubers is **Gibberellins**.

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