The phenomenon which shortens vegetative period and hastens flowering is

Options

A. Etiolation
B. Vernalisation
C. Photoperiodism
D. Parthenocarpy.

Answer

To solve the question regarding the phenomenon that shortens the vegetative period and hastens flowering, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for a phenomenon that reduces the time a plant spends in its vegetative stage and accelerates the flowering process.

2. **Analyze the Options**:
- **Etiolation**: This is a condition where a plant grows in partial or complete absence of light, leading to elongated stems and yellow leaves. It does not promote flowering.
- **Vernalization**: This refers to the process where exposure to prolonged cold or winter conditions induces flowering in plants. It effectively shortens the vegetative period and promotes flowering.
- **Photoperiodism**: This is the response of plants to the relative lengths of day and night, influencing flowering but not necessarily shortening the vegetative period.
- **Parthenocarpy**: This is the development of fruit without fertilization, which does not relate to the vegetative period or flowering.

3. **Identify the Correct Answer**: Based on the analysis, the correct answer is **Vernalization**. This phenomenon specifically shortens the vegetative period and hastens flowering by exposing plants to cold temperatures.

4. **Conclusion**: The phenomenon that shortens the vegetative period and hastens flowering is **Vernalization**.