After karyogamy followed by meiosis, spores are produced exogenously in

Options

A. Saccharomyces
B. Agaricus
C. Alternaria
D. Neurospora

Answer

To solve the question "After karyogamy followed by meiosis, spores are produced exogenously in," we will follow these steps:

### Step 1: Understand Key Terms
- **Karyogamy**: This is the fusion of two nuclei, typically occurring after fertilization in sexual reproduction.
- **Meiosis**: This is a type of cell division that reduces the chromosome number by half, resulting in the production of haploid spores from a diploid zygote.
- **Exogenous Spores**: These are spores produced outside of the parent organism or structure.

### Step 2: Identify the Process
After karyogamy, the diploid zygote undergoes meiosis to produce haploid spores. The question specifically asks for the type of fungi that produces these spores exogenously.

### Step 3: Analyze the Options
1. **Saccharomyces**: This is a genus of yeast (Ascomycetes) that produces ascospores endogenously, meaning the spores are formed inside a structure (ascus).
2. **Agaricus**: This is a genus of mushrooms (Basidiomycetes) that produces basidiospores exogenously, meaning the spores are formed outside of the parent structure.
3. **Alternaria**: This is a genus of Deuteromycetes that does not produce sexual spores, so it cannot be the answer.
4. **Neurospora**: This is another genus of Ascomycetes that produces ascospores endogenously.

### Step 4: Conclusion
Among the options, **Agaricus** is the only genus that produces spores exogenously after karyogamy and meiosis. Therefore, the answer to the question is **Agaricus**.

### Final Answer
**Agaricus**