Which one of the following is not a biofertilizer?

• A. Agrobacterium
• B. Rhizobium
• C. Nostoc
• D. Mycorrhiza

To determine which option is not a biofertilizer, let's look at each choice:

Options Overview

• Agrobacterium: This is a genus of bacteria known for its role in plant genetic engineering, but it is not typically classified as a biofertilizer.
• Rhizobium: These bacteria form symbiotic relationships with legumes, fixing nitrogen in the soil, making them a well-known biofertilizer.
• Nostoc: This is a cyanobacterium that can fix nitrogen and is used as a biofertilizer in some agricultural practices.
• Mycorrhiza: These are fungi that form beneficial associations with plant roots, enhancing nutrient uptake, and are considered biofertilizers.

Final Answer

Based on the definitions, the correct answer is Agrobacterium, as it is not classified as a biofertilizer.