Norin gene' of dwarfness in wheat originated through spontaneous mutation in

Options

A. India
B. Japan
C. Mexico
D. U.S.S.R.

Answer

### Step-by-Step Solution:

1. **Understanding the Norin Gene**: The Norin gene is associated with dwarfness in wheat. It is important to recognize that this gene plays a significant role in the development of semi-dwarf wheat varieties, which are crucial for agricultural productivity.

2. **Identifying the Origin**: The question asks about the origin of the Norin gene. It is essential to know where this gene was first identified or developed.

3. **Researching the Background**: The Norin 10 variety of wheat, which carries the Norin gene, was developed by Gonjirō Inazuka at an experimental station in Japan. This variety is known for its short stature and high yield, making it suitable for various climatic conditions.

4. **Evaluating the Options**: The options provided are India, Japan, Mexico, and USSR. Based on the background research, we need to determine which of these countries is associated with the development of the Norin gene.

5. **Conclusion**: Since the Norin gene of dwarfness in wheat originated through spontaneous mutation in Japan, the correct answer is Japan.

### Final Answer:
The Norin gene of dwarfness in wheat originated through spontaneous mutation in **Japan**.

---