Yield of paddy field can be increased by application of

Options

A. Iron bacteria
B. Nostoc/Anabaena
C. Archaebacteria
D. Symbiotic bacteria

Answer

To answer the question about how to increase the yield of paddy fields, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks how the yield of paddy fields can be increased through specific applications.

2. **Identifying Key Options**: The options provided are:
- Iron bacteria
- Nostocanabina
- Archaebacteria
- Symbiotic bacteria

3. **Analyzing Each Option**:
- **Iron Bacteria**: These are not known to significantly enhance paddy yield. They mainly oxidize iron and are not directly related to nitrogen fixation.
- **Nostocanabina**: This is a type of blue-green algae (cyanobacteria) that can fix atmospheric nitrogen, making it beneficial for paddy fields. It grows well in water and can enhance soil fertility.
- **Archaebacteria**: These are a group of microorganisms that do not play a significant role in increasing paddy yield.
- **Symbiotic Bacteria**: While some symbiotic bacteria can help in nitrogen fixation, they are not specifically known to be used in paddy fields like Nostocanabina.

4. **Conclusion**: Among the options, Nostocanabina is the most suitable choice as it can fix atmospheric nitrogen and increase the nitrogen content in the soil, leading to improved yield in paddy fields.

5. **Final Answer**: The yield of paddy fields can be increased by the application of **Nostocanabina**.