Vikash went to vegetable market with his elder sister, a M.Sc Botany student. There he saw many varieties of different vegetables such as different kinds of chilies (short, long, round, pungent, less pungent, green reddish, orange), several varieties of potato and tomatoes. He asked his sister the following questions. (i) What is the need of producing so many varieties of different crop plants. (ii) What is the name of branch of science which deals with crop improvement ? (iii) What are the methods used by plant breeders ? (iv) What is hybridization ?