[A]: Incompatibility is a gene physiological process.
[R]: Moderately high temperatures are also known to reduce self incompatibility reaction in certain plants.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To analyze the assertion and reason provided in the question, we will break it down step by step.

### Step 1: Understand the Assertion
The assertion states that "Incompatibility is a gene physiological process."
- **Explanation**: Incompatibility refers to the inability of certain plants to fertilize themselves or to accept pollen from certain other plants. This is often due to genetic factors that affect the reproductive process. Therefore, the assertion is **true**.

### Step 2: Understand the Reason
The reason states that "Moderately high temperatures are also known to reduce self-incompatibility reactions in certain plants."
- **Explanation**: It is known that environmental factors, including temperature, can influence the physiological processes in plants. Specifically, moderately high temperatures can indeed reduce the self-incompatibility reactions, allowing for fertilization that would otherwise not occur. Thus, this reason is also **true**.

### Step 3: Analyze the Relationship Between Assertion and Reason
Now we need to determine if the reason correctly explains the assertion.
- **Explanation**: While both the assertion and the reason are true, the reason does not explain why incompatibility is a gene physiological process. The assertion is about the genetic basis of incompatibility, while the reason discusses the effect of temperature on the self-incompatibility reaction. They are related but do not directly explain one another.

### Conclusion
Both the assertion (A) and the reason (R) are true, but the reason is not a correct explanation of the assertion. Therefore, the correct answer is that both A and R are true, but R is not the correct explanation of A.

### Final Answer
Both A and R are true, but R is not the correct explanation of A.

---