What is meant by emasculation? When and why does a plant breeder employ this technique?

(N/A) Emasculation is the process of removing anthers from bisexual flowers without affecting the female reproductive part (pistil),which is used in various plant hybridization techniques.
Emasculation is performed by plant breeders in bisexual flowers to obtain the desired variety of a plant by crossing a particular plant with the desired pollen grain. To remove the anthers,the flowers are covered with a bag before they open. This ensures that the flower is pollinated by pollen grains obtained from desirable varieties only. Later,the mature,viable,and stored pollen grains are dusted on the bagged stigma by breeders to allow artificial pollination to take place and obtain the desired plant variety.