Modern farmer's can increase the yield of paddy upto 50% by the use of :-

Options

A. Cyanobacteria
B. Rhizobium
C. Cyaanobacteria in Azolla pinnata
D. Farm yard meanure

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how modern farmers can increase the yield of paddy (rice) by up to 50%.

2. **Identifying Key Components**: The options provided include cyanobacteria, rhizobium, Azolla pinnata, and farmyard manure. We need to determine which of these is most effective in increasing paddy yield.

3. **Exploring Azolla pinnata**: Azolla pinnata is a free-floating freshwater fern that has a symbiotic relationship with cyanobacteria (specifically, Anabaena). This relationship is crucial because it allows Azolla to fix atmospheric nitrogen.

4. **Role of Cyanobacteria**: Cyanobacteria, particularly Anabaena, have specialized cells called heterocysts that contain the enzyme nitrogenase. This enzyme is responsible for fixing nitrogen from the atmosphere, making it available for plant uptake.

5. **Benefits of Nitrogen Fixation**: Nitrogen is an essential nutrient for plant growth. By using Azolla pinnata in paddy fields, farmers can enhance the nitrogen content of the soil, which is vital for the growth of rice plants.

6. **Conclusion**: Given the ability of Azolla to fix nitrogen through its symbiotic relationship with cyanobacteria, it serves as an effective biofertilizer. Therefore, modern farmers can increase the yield of paddy by using Azolla pinnata.

7. **Final Answer**: The correct answer to the question is Azolla pinnata.

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