In artificial hybridisation, why are the anthers removed from the flower buds of a female parent that bears bisexual flowers?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → To prevent the flower's own pollen from reaching its stigma
In artificial hybridisation, the breeder must make sure that only the desired pollen grains reach the stigma. In a bisexual flower the anthers sit in the same flower as the stigma, so its own pollen could pollinate it. The anthers are therefore removed from the flower bud before they dehisce. This step is called emasculation.
Option (1) To collect mature pollen grains for dusting on other flowers — Incorrect. Pollen for the cross is collected from the anthers of the male parent, not from the anthers removed from the female parent.
Option (2) To overcome self-incompatibility in the pistil — Incorrect. Self-incompatibility is a genetic mechanism of the pistil that stops self-pollen from fertilising the ovules. Removing anthers does not change it.
Option (3) To prevent the flower's own pollen from reaching its stigma — Correct. Removing the anthers before they dehisce ensures that the flower's own pollen cannot reach its stigma. Only the desired pollen is used.
Option (4) To make the stigma receptive earlier — Incorrect. Removing anthers does not change when the stigma becomes receptive. The breeder waits for the stigma of the bagged flower to become receptive before dusting the pollen.
NCERT Extract:
Pollination – “… 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. 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.”