Pollination, it is results from the transfer of pollen to the stigma. There is two types pollination: self-pollination and cross-pollination. Continuous self-pollination or inbreeding leads to inbreeding depression. Cross pollination leads to out breeding with the help of methods or devices

In plant, autogamy is prevented by several ways:

1) Pollen and stigma may not be coordinated.

2) Different position of the anther and stigma.

3) Production of unisexual flowers