Cross-pollination

When pollination occurs between flowers on two different plants of the same species, it is called cross-pollination.

or

Transfer of pollen grains from the anther of a flower from one plant to the stigma of the flower on another plant is called cross-pollination

In this pollination, pollen grains of one plant reach the stigma of a flower of another plant of the same species.

• It involves two plants of the same species to produce seeds.
• It is the only type of pollination that brings genetically different pollen grains to the stigma.
• Transfer of pollen grains from the anther to the stigma of a different plant (Xenogamy; allos = different; gamos = marriage).
• Cross-pollination is a device to bring about genetic recombination and variation.
• Pollen grains require some agencies (pollinators) to reach the stigma.

Xenogamy

1. Produces genetic recombination → new useful characters in offspring
2. Offspring are healthier and more vigorous (called Hybrid Vigour)
3. Seeds are larger, more viable, and germinate better
4. Increases plant's adaptability to new environments
5. Helps produce disease-resistant, high-yielding varieties
6. Promotes new variety formation

1. Chance factor - depends on external agents; pollination may fail
2. Wastage - plant produces huge amounts of pollen (energy costly)
3. May introduce undesirable characters due to gene mixing
4. Distance barrier - plants far apart may not get pollinated
5. Uneconomical - plant must grow large, colourful, scented flowers to attract pollinators