Improvement in Food Resources — Science STD 9 — Question

Varietal improvement refers to development of new varieties of crops which are more adapted to local conditions and are better in terms of yield and other characteristics like disease and drought resistance, water requirement, nutrient content etc.
Reasons for varietal improvement:
Population increases in geometrical progression while food supply in arithmetical. Hence better varieties are needed to increase food production and quality. The new varieties should be superior to the predecessors and have desirable agronomic characteristics.