Question

How to improve crop variety ?

Answer 1

using better quality seeds HYV
good fertilization and irrigation

Answer 2

variety improvement depends upon newer crop varieties that can give , this is can be achieved by two methods i.e. Hybridization and genetically modified crops :-
  - on improving biotic resistances by which plants can be able to fight with pathogens .
  - better response from fertilizers and manures 
  - better suited agronomic characters fro the various requirements   
  - increased abiotic resistance by which crop can with stand the adverse condition . ( flood , drought , salinity , heat cold and frost )  
  - better quality of climate conditions .
  - and also to maintain quality and quality of the crops .