Q.What is bagging technique? How is it useful in a plant breeding programme?

Bagging is a technique used in plant breeding where individual flowers or inflorescences are covered with a bag — usually made of paper, muslin cloth, or polythene — before they open. The purpose is to prevent unwanted pollen from reaching the stigma, thereby ensuring that only the desired pollen (introduced later by the breeder) fertilises the flower. This is a critical step in controlled pollination.

In a plant breeding programme, bagging is useful in the following ways:

• It prevents contamination by foreign pollen from the same or other varieties, which would ruin the cross.
• It allows the breeder to carry out artificial hybridisation with certainty — only the pollen that the breeder deliberately dusts onto the stigma will fertilise the ovules. …

In plant breeding, the goal is often to combine desirable traits from two different parent plants. But plants, especially those that are self-pollinating or wind-pollinated, can easily be contaminated by pollen from unknown sources. This is where the bagging technique comes in — it is a simple but essential method of physical isolation.

The idea is straightforward: before a flower’s anthers release pollen (or just before the stigma becomes receptive), the flower or inflorescence is enclosed in a bag made of paper, muslin cloth, or a similar material. The bag prevents any foreign pollen from reaching the stigma. At the same time, it allows air and light to pass through, so the flower remains healthy. Once the bag is in place, the breeder can later introduce pollen from a chosen male parent — either by dusting it onto the stigma and rebagging, or by removing the bag briefly for hand pollination.

Now, how is bagging useful in a plant breeding programme? Its value lies in three key areas.

First, it ensures controlled pollination. Without bagging, a breeder cannot be certain which male parent actually fertilised the female flower. The bag acts as a barrier, so only the pollen deliberately applied by the breeder reaches the stigma. This is critical for making specific crosses — for example, crossing a high-yielding wheat variety with a disease-resistant one.

Second, bagging helps in producing pure lines. In self-pollinating crops like rice, wheat, or peas, breeders often need to maintain a variety’s purity. By bagging flowers before they open, the plant is forced to self-pollinate, and the resulting seeds are genetically identical to the parent. This is the foundation of developing inbred lines and maintaining true-breeding varieties. …