What are the various factors for which varietal improvement is done? Explain.

Explanation

### Step-by-Step Solution:

1. **Higher Yield**: One of the primary factors for varietal improvement is to achieve a higher yield. This means that the improved variety of a crop should produce more produce per unit area, which is essential for meeting the food demands of a growing population.

2. **Improved Quality of Crop**: Another important factor is the quality of the crop. Varietal improvement aims to enhance the nutritional value, taste, and other quality attributes of the crops, making them more appealing to consumers and increasing their market value.

3. **Biotic and Abiotic Resistance**: Varietal improvement also focuses on developing crops that can withstand various biotic (living) and abiotic (non-living) stresses. Biotic factors include pests and diseases, while abiotic factors encompass environmental conditions such as temperature, sunlight, pH, and rainfall. Improved varieties should be resilient to these factors to ensure better survival and productivity.

...