Pathogenic entity which is responsible for the production of tumour in most dicot plants is

Options

A. Retrovirus
B. Bacteriophage
C. Ti plasmid
D. Vector

Answer

**Step-by-Step Solution:**

1. **Identify the Pathogenic Entity**: The question asks for the pathogenic entity responsible for tumor production in dicot plants. The primary pathogenic entity known for this effect is a bacterium.

2. **Name the Bacterium**: The specific bacterium responsible for tumor formation in dicot plants is *Agrobacterium tumefaciens*. This bacterium is well-known for inducing tumor formation through its interaction with plant cells.

3. **Understand the Mechanism**: *Agrobacterium tumefaciens* transfers a segment of its DNA (known as T-DNA) into the plant's genome, which leads to the formation of tumors. This process is part of the bacterium's natural life cycle and is used in biotechnology for creating transgenic plants.

4. **Application in Biotechnology**: The T-DNA can be modified to include desirable genes, allowing scientists to create genetically modified plants that can express traits such as disease resistance or increased yield.

5. **Conclusion**: Therefore, the pathogenic entity responsible for tumor production in most dicot plants is *Agrobacterium tumefaciens*.

**Final Answer**: *Agrobacterium tumefaciens*

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