Class 12 Biology Practical: To Perform Emasculation, Bagging and Tagging for Controlled Pollination | Practical File

Controlled pollination is an essential technique in plant breeding. In this Class 12 Biology practical, students learn how to perform emasculation, bagging, and tagging to ensure that only desired pollen grains fertilize the flower. This practical helps understand hybridization, crop improvement, and reproductive biology in plants.

Aim: To perform emasculation, bagging and tagging for controlled pollination

Principle: Conventional plant breeding programmes involve bringing under human control reproductive processes that lead to seed and fruit formation. For this controlled pollination is desirable using male and female parent having desired traits. One of the process that can be easily brought under human control is emasculation. For this the knowledge of flower structure, mechanism of pollination, fertilisation and physiology of flowering is essential for this. In emasculation technique the stamens are removed before anthesis to obtain female parent and pollen from the desired male parent is transferred on to its stigma.

Requirement: Ornamental plants/ wild plants bearing large bisexual flower, magnifying lens, tweezers, small sharp scissors, brush, alcohol, rubber bands, paper bags, paper clips and tags

Procedure

(i) Select a flower in bud condition where antheses has not occurred. Open the bud carefully and remove the stamens. Mark this as female parent plant.

(ii) Cover the emasculated flower with a plastic bag to protect it from undesired pollen (Bagging) (Fig. 12.2). The bag should be held securely in place with a paper clip/ string/thread. Select the size of bag in accordance with the flower size. Bags must be transparent with minute pores.

(iii) Bring into physical contact anthers of a desired male plant containing mature pollen grains with the stigmatic surface of emasculated female flower. Use tweezers/brush if necessary to dust the stigmatic surface with pollen.

(iv) Cover the pollinated flower again with the bag immediately. For identification, label the female parent (Tagging). Each pollinated flower should bear a label containing the name of the seed parent, the letter X (to signify a cross), the name of the pollen parent, and the date on which the cross was effected.

OBSERVATION

Afier controlled pollination . the plant is kept undisturbed and under observation till seed setting and harvesting, This leads to the success of the experiment.

RESULT

By the process of controlled pollination, the female parent Plant will produce seeds of the desired characteristics.

Precautions

A good variety of parent plant should be selected.
Care should be taken while doing emasculation.
After controlled pollination. proper care of experimental plant should be done till seed setting