Sexual Reproduction In Flowering Plants — BIOLOGY STD 12 Science — Question

→ A breeder is interested in crossing different species and often genera to combine desirable characters to produce commercially 'superior' varieties. Artificial hybridisation is one of the major approaches of crop improvement programme.
→ In such crossing experiments it is important to make sure that only the desired pollen grains are used for pollination and the stigma is protected from contamination (from unwanted pollen). This is achieved by emasculation and bagging techniques.
Emasculation:
→ If the female parent bears bisexual flowers, removal of anthers from the flower bud before the anther dehisces using a pair of forceps is necessary. This step is referred to as emasculation.
Bagging :
→ Emasculated flowers have to be covered with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen. This process is called bagging.
Rabagging:
→ When the stigma of bagged flower attains receptivity, mature pollen grains collected from anthers of the male parent are dusted on the stigma, and the flowers are rebagged, and the fruits are allowed to develop.
→ If the female parent produces unisexual flowers, there is no need for emasculation. The female flower buds are bagged before the flowers open.
→ When the stigma becomes receptive, pollination is carried out using the desired. pollen and the flower rebagged.