Pollen grains do not germinate on the stigma of the same flower. The Phenomenon is

Options

A. Prepotency
B. Self sterility
C. Dicliny
D. Dichogamy.

Answer

To solve the question "Pollen grains do not germinate on the stigma of the same flower. The Phenomenon is", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question states that pollen grains do not germinate on the stigma of the same flower. We need to identify the phenomenon that describes this situation.

2. **Analyze the Options**: The options provided are:
- A) Prepotency
- B) Self-sterility
- C) Decline
- D) Dichogamy

3. **Evaluate Each Option**:
- **Prepotency**: This term generally refers to the ability of certain pollen to fertilize ovules more effectively than others, which does not apply here.
- **Self-sterility**: This is a condition where pollen from the same flower cannot fertilize its ovules, indicating sexual incompatibility. This matches the situation described in the question.
- **Decline**: This term does not relate to pollen germination or fertilization and is not relevant to the question.
- **Dichogamy**: This refers to the maturation of male and female reproductive organs at different times to prevent self-fertilization. However, the question specifies the same flower, making this option incorrect.

4. **Identify the Correct Answer**: Based on the analysis, the correct answer is **B) Self-sterility**. This phenomenon indicates that even if pollen lands on the stigma of the same flower, it cannot germinate due to sexual incompatibility.

5. **Conclusion**: The phenomenon where pollen grains do not germinate on the stigma of the same flower is called **self-sterility**.