Hybridization : It is the technique of introducing characters of 2 desirable species into a single offspring (hybrid) by means of artificial pollination to create new genetic combination. It is mixing of two different traits, differing in their genetic composition. As a result of hybridization, hybrid varieties of cereals, oil seeds, pulses, sugarbeet, onion, tomato etc.
Technique of Hybridization in plants :
1. Selection and isolation of plants : First, the plants to be used as male and female are selected. These plants are induced to flower at the same time. Crossing is done in a greenhouse controlled condition.
2. Emasculation. When the two parent plants have bisexual flowers, the stamens of one plant are removed in the bud stage. This is called emasculation.
3. Bagging. Male and female flowers are covered with polythene or paper bags so that no foreign pollen may fall on the stigma. This is called bagging.
4. Pollination. Bags are opened at the time when the act of pollination is to be performed. After that the female cross-pollinated flower is again bagged. If the plants are dioecious, the male plants are completely eliminated from the vicinity of the female plants which are to be Cross-pollinated by pollen of a desired species.
Explain the following :
(i) Grafting
(ii) Vital capacity
(iii) Ureotelism
(iv) Epigeal germination.