For the crop improvement, plant breeder required different types of resistant gene. The source of these resistant gene maybe:

Options

A. Cultivated varieties
B. Germplasm collection
C. Wild relatives
D. All of the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Requirement**: Plant breeders are focused on crop improvement, specifically developing resistance against various pests and diseases that can affect crop yield.

2. **Identifying Resistant Genes**: To achieve this, plant breeders require different types of resistant genes that can provide the necessary traits for pest resistance.

3. **Sources of Resistant Genes**:
- **Cultivated Varieties**: These are existing crop varieties that have already shown resistance to certain pests or diseases. Breeders can utilize these varieties to introduce resistant traits into new crops.
- **Germplasm Collection**: Germplasm refers to the genetic material of plants. Collecting germplasm allows breeders to access a wide range of genetic diversity, which may include resistant genes.
- **Wild Relatives**: Wild relatives of cultivated crops often possess unique traits, including resistance to pests and diseases. These can be valuable sources of resistant genes that can be incorporated into cultivated varieties.

4. **Conclusion**: Therefore, the sources of resistant genes for crop improvement can be from cultivated varieties, germplasm collections, and wild relatives. The correct answer is "all of the above."

**Final Answer**: The sources of resistant genes may be cultivated varieties, germplasm collections, wild relatives, and all of the above.

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