Loose smut of wheat is caused by

Options

A. Ustilago tritici
B. Cystopus tritici
C. Puccinia graminis
D. Aspergillus graminis.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the causative agent of loose smut of wheat. Loose smut is a fungal disease that affects wheat crops.

2. **Identifying the Options**: The options provided are:
- A) Ustilago tritici
- B) Cystopus tritici
- C) Puccinia graminis
- D) Aspergillus graminus

3. **Recognizing the Type of Disease**: Loose smut is a type of disease known as a smut disease, which is typically caused by fungi belonging to the class Basidiomycetes.

4. **Analyzing Each Option**:
- **Ustilago tritici**: This is known to cause loose smut of wheat. It replaces the grain with spores, leading to the disease.
- **Cystopus tritici**: This fungus is known to cause rust disease, not loose smut.
- **Puccinia graminis**: This fungus is responsible for stem rust in cereal crops, not loose smut.
- **Aspergillus graminus**: This fungus is known to cause diseases in maize, not wheat.

5. **Selecting the Correct Answer**: Based on the analysis, the correct answer is **A) Ustilago tritici**.

6. **Conclusion**: Therefore, loose smut of wheat is caused by Ustilago tritici.

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