List the factors for which variety improvement is done?

The factors for which a variety of improvement is done are:

(i) Higher yield: To increase the productivity of the crop per acre.

(ii) Improved quality: The quality of crop products vary from crop to crop. E.g., protein quality is important in pulses, oil quality in oilseeds, preserving quality in fruits and vegetables.

(iii) Biotic and abiotic resistance: Biotic factors are the diseases, insects, and nematodes while abiotic factors are the drought, salinity, waterlogging, heat, cold and frost which affect the crop productivity. Varieties resistant to these factors (stresses) can be improved to increase crop production.

(iv) Change in maturity duration: Shorter maturity period of crop reduces the cost of crop production and makes the variety economical. Uniform maturity makes the harvesting process easy and reduces losses during harvesting.

(v) Wider adaptability: It allows the crops to be grown under different climatic conditions in different areas.

(vi) Desirable agronomic characteristics: It increases productivity, for example, tallness and profuse branching are desirable characters for fodder crops; while the dwarf character is desired in cereals so that fewer nutrients are consumed by these crops.