Induction of flowering by low temperature treatment is :

Options

A. Vernalization
B. Cryobiology
C. Photoperiodism
D. Prunning

Answer

To answer the question "Induction of flowering by low temperature treatment is:", we need to analyze the provided options and understand the relevant biological processes.

### Step-by-Step Solution:

1. **Understand the Concept**: The question is asking about the process through which flowering in plants is induced by exposure to low temperatures. This is a specific phenomenon in plant biology.

2. **Evaluate the Options**:
- **Option 1: Vernalization**: This is the process where flowering is induced by prolonged exposure to cold temperatures. It is a well-known method used in agriculture to ensure that certain plants flower at the right time.
- **Option 2: Cryobiology**: This is a field of study that focuses on the effects of low temperatures on living organisms, but it does not specifically refer to the induction of flowering.
- **Option 3: Photo-periodism**: This refers to the response of plants to the length of day and night, affecting flowering but not directly related to low temperature.
- **Option 4: Pruning**: This is a horticultural practice involving the selective removal of parts of a plant, which does not relate to flowering induction by low temperatures.

3. **Identify the Correct Answer**: Based on the definitions and explanations of each option, the correct answer is **Vernalization**. This process specifically involves the induction of flowering in response to low temperature treatment.

4. **Conclusion**: Therefore, the induction of flowering by low temperature treatment is called **Vernalization**.

### Final Answer:
Induction of flowering by low temperature treatment is called **Vernalization**.