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

Explanation

If the female parent bears bluexual flowers, removal of anthers from the flower bud before the anther dehisces using a pair of forceps is necessary. This step is called emasculation. In crossing experiments, it is necessary that only desired pollen grains are used for pollination and stigma is protected contamination (from unwanted pollen). This is achieved by emasculation and bagging,