(i) What is the need of producing so many varieties of different crop plants ?
(ii) What is the need of branch of science which deals with crop improvement ?
(iii) What are the methods used by plant breeders ?
(iv) What is hybridization ?

Explanation

(i) There exists a great variety of agro climatic conditions and different varieties are suitable for reparing different food items. A variety of a crop plant generally gives good yield in a particularly set of agro climatic conditions. Therefore, different varieties with varying traits are produced keeping in view the agro climate conditions and market demands.
(ii) Plant Breeding
(iii) These are : (a) Introduction (b) Selection (c ) Hybridization (d) Recombinant DNA Technology or Genetic Engineering.
(iv) It is a technique in which the two plants having the desired characters are made to cross and develop seeds. Engineering.
(iv) It is a technique in which the two plants having the desired characters are made to cross and develop seeds.