The three factors for improving crop variety are:

Resistance: Various biotic factors like insects, parasites, diseases, etc. and abiotic factors like hot, cold, drought, salinity, etc. affect the crop production. Developing resistance to both living and non-living factors can give a high yield.

Maturity period: The short growth period of crops helps farmers in multiple rounds of cultivation in less expenditure. Also, the uniform maturity of crops makes them easy to harvest.

Adaptation: It will develop tolerance and allows the crops to grow under different climatic conditions and in different areas. (All points are with Explanation)