What is meant by emasculation? When and why does a plant breeder employ this technique?
Emasculation refers to the removal of anthers from the flower bud before the anther dehisces using a pair of forceps. This process is necessary when the female parent bears bisexual flowers in plant breeding experiments.
A plant breeder employs emasculation during artificial hybridisation experiments as part of crop improvement programmes. This technique is used when the female parent bears bisexual flowers (it is not needed for unisexual flowers). The purpose is to ensure that only the desired pollen grains are used for pollination and to protect the stigma from contamination with unwanted pollen. This allows breeders to combine desirable characters from different species and often genera to produce commercially 'superior' varieties.
Explanation
The question asks about emasculation, which is a key technique in artificial hybridization. According to the NCERT textbook context, emasculation is specifically defined as the removal of anthers from flower buds before they dehisce. The context clearly explains that this technique is part of artificial hybridization in crop improvement programmes, where breeders want to cross different species to combine desirable characters. The main purpose is preventing unwanted pollen contamination to ensure only desired pollen reaches the stigma.