Insect pest resistant Bt-cotton plant was developed using:

Options

A. somaclonal variation
B. micropropagation
C. somatic hybridisation
D. transgenic technology

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how the insect pest-resistant Bt-cotton plant was developed.

2. **Identifying the Key Term**: The term "Bt-cotton" refers to cotton that has been genetically modified to express a protein from the bacterium Bacillus thuringiensis (Bt), which provides resistance against certain insect pests.

3. **Recognizing the Technology Used**: The development of Bt-cotton involves genetic engineering, specifically the incorporation of a gene from Bacillus thuringiensis into the cotton plant's genome. This process is known as transgenic technology.

4. **Gene Isolation**: The specific gene isolated from Bacillus thuringiensis is known as the cry gene. This gene encodes for the production of a protein called Cry protein, which has insecticidal properties.

5. **Function of Cry Protein**: The Cry protein produced by the transgenic Bt-cotton plant is toxic to certain insect pests, particularly the cotton bollworm, thereby providing the plant with pest resistance.

6. **Conclusion**: Since the question is about the technology used to develop the insect pest-resistant Bt-cotton, the correct answer is transgenic technology.

**Final Answer**: The insect pest-resistant Bt-cotton plant was developed using transgenic technology.

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