Considering the genetic basis of self- incompatibility which of the following options is correct. Male plant is `S_1 S_3` and female plant is `S_1 S_2`

Options

A.
B.
C.
D.

Explanation

To solve the question regarding the genetic basis of self-incompatibility between a male plant with genotype `S1 S3` and a female plant with genotype `S1 S2`, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding Self-Incompatibility**:
Self-incompatibility is a genetic mechanism in flowering plants that prevents self-fertilization and promotes outcrossing. This is often controlled by specific alleles known as S-alleles.

2. **Identifying the Genotypes**:
- The male plant has the genotype `S1 S3`.
- The female plant has the genotype `S1 S2`.

3. **Analyzing the Alleles**:
- The female plant has S-alleles `S1` and `S2`.
- The male plant has S-alleles `S1` and `S3`.

4. **Interaction of Alleles**:
- When pollen from the male plant (which has `S1` and `S3`) lands on the stigma of the female plant (which has `S1` and `S2`), the S-alleles will interact.
- The `S1` allele from the male will recognize the `S1` allele from the female, leading to a self-incompatibility reaction. This means that the pollen with `S1` will not be able to germinate on the stigma of the female plant.

5. **Successful Pollen Tube Formation**:
- The pollen that carries the `S3` allele from the male plant will not have a matching allele in the female plant (which has `S1` and `S2`).
- Therefore, the pollen with `S3` can successfully germinate and form a pollen tube, allowing fertilization to occur.

6. **Conclusion**:
- Since the pollen with `S1` cannot fertilize due to self-incompatibility, the only successful fertilization will occur with the pollen carrying `S3`. Thus, the correct option regarding the genetic basis of self-incompatibility in this scenario is that the pollen tube formed will be from the `S3` allele.

### Final Answer:
The correct option is that the pollen tube formed will be from the `S3` allele.

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