Introduction of foreign genes for improving genotype is
Or
Insertion or deletion of one or more new genes which are absent in an organism by artificial method (not by reproduction ) is called as

Options

A. biotechnology
B. vernalization
C. tissue culture
D. genetic engineering .

Explanation

To solve the question regarding the introduction of foreign genes and the alteration of an organism's genotype, we can break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the process of introducing foreign genes into an organism or altering its genetic makeup by artificial means, rather than through natural reproduction.

2. **Identifying Key Terms**:
- "Foreign genes": These are genes that originate from a different organism.
- "Improving genotype": This refers to enhancing the genetic characteristics of an organism.
- "Insertion or deletion of genes": This indicates that genes can be added or removed to modify the organism's traits.

3. **Analyzing the Options**:
- **Biotechnology**: This is a broad field that encompasses various techniques involving living organisms, but it does not specifically refer to the alteration of genes.
- **Vernalization**: This is a process related to the induction of flowering in plants through exposure to cold temperatures. It is not relevant to gene alteration.
- **Tissue Culture**: This technique involves growing cells or tissues in a controlled environment but does not directly refer to the introduction or alteration of genes.
- **Genetic Engineering**: This is the specific field that deals with the direct manipulation of an organism's genes, including the introduction of foreign genes and the insertion or deletion of genes.

4. **Conclusion**: Based on the definitions and the context provided, the correct answer is **Genetic Engineering**. This field specifically focuses on the alteration of genetic material in organisms through artificial methods.

### Final Answer:
The introduction of foreign genes for improving genotype or the insertion or deletion of one or more new genes which are absent in an organism by artificial methods (not by reproduction) is called **Genetic Engineering**.