Pollination: what does self-fertile mean?

What's pollination? why is it so useful? Which are the differences between a self-fertile or not plant?

Plants, as all other organisms, have to spread their species in the world. Every plant has its own strategy to disperse its seeds as far as possible to give the best habitat to the future plants.

A species that disperses its seeds farther and better will have an evolutionary advantage. That plant will spread over a larger area and shall increase in number. This is one of the concept of the theory of evolution.

Charles Darwin: 12 Feb 1809 - 19 Apr 1882

Fruits are produced (except rare cases) after the pollen has fertilized the ovule and they protect the seeds. Moreover fruits attract animals which, eating them, spread the seeds far away from the mother-plant allowing them to grow without competition for nutrients and light.

                             

                         

Even if a flower has both the male and female parts not alway can self-pollinate. To increase the genetic variability the nature, in many plants, has evolved  a system by which the pollen of a plant cannot pollinate the ovule of the same plant. This kind of plants are named self-sterile.

Many varieties of apple or cherry are self sterile, this means that you need at least two different apple plants to have fruits. Self-sterile plants need cross-pollination to bear fruits.

Instead a self-fertile plant can bear fruit also with auto-pollination, so the presence of different plants is not strictly necessary. Its pollen is able to pollinate the ovule of the same plant. Apricots or peaches are generally self-fertile plants.

If you want to eat fruits from a self-sterile plant you MUST :

• Have at least two plants of the same species (e.i. two apples)
• These two plants must be different cultivars (two "Stark" apple are genetically identical)
• They must flower at the same time
• They must be planted not too far from each other, remember that bees fly in a radius of 1 mile.