In artificial hybridisation, bagging is done to:

Prevent contamination of stigmas with unwanted pollens

The correct answer is Option (4)- Prevent contamination of stigmas with unwanted pollens

The purpose of bagging in artificial hybridization is to prevent contamination of the stigma with unwanted pollen.

Bagging involves covering the emasculated or female flower with a bag made of suitable material, such as butter paper. The bag serves as a physical barrier that isolates the flower and protects the stigma from the entry of unwanted pollen grains. This is crucial in ensuring controlled pollination and increasing the chances of obtaining the desired hybrid offspring.

By bagging the flower, the stigma is shielded from external sources of pollen, such as pollen from other plants or pollen carried by insects or wind. This is important because in artificial hybridization, breeders want to ensure that only the desired pollen grains, collected from the male parent plant, are used for pollination.

Contamination of the stigma with unwanted pollen can lead to undesired cross-pollination, resulting in the introduction of genetic material that may not align with the breeding objectives. Bagging prevents this unwanted cross-pollination by creating a protective barrier around the flower, thereby maintaining the purity of the intended cross.

In addition to preventing contamination with unwanted pollen, bagging can also provide some protection against insect damage and minimize the risk of the stigma drying out by maintaining a controlled environment around the flower.

Overall, the purpose of bagging in artificial hybridization is to prevent the stigma from being contaminated with unwanted pollen, ensuring controlled pollination and increasing the chances of obtaining the desired hybrid offspring with specific traits.