What is meant by .emasculation?

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

Emasculation is the process of removal of stamens from a bisexual flower before they shed pollen in order to prevent self-pollination and permit cross-pollination of . stigma with unwanted pollen. During breeding, the breeder wants to make sure that the desired pollen grains are used for pollination and the stigma is protected from contamination (from unwanted pollen).
This technique is employed as the first step before pollination. A plant breeder employs this technique to select specific traits in order to get disease-resistant plants.