Self-Incompatibility: How Plants Avoid Inbreeding

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Plants, being anchored in position, have a special problem in this regard. Many employ the services of animals (e.g., insects, birds, bats) to transfer pollen from plant to plant. But if the flowers have both sex organs: what is to prevent the pollen from fertilizing its own eggs?

A variety of solutions have been tried in the plant kingdom.

These include: But the vast majority of angiosperms have perfect flowers; that is containing both male and female sex organs. So how do they avoid self-fertilization?

Sporophytic Self-Incompatibility (SSI)

This form of self-incompatibility has been studied intensively in members of the mustard family (Brassica), including turnips, rape, cabbage, broccoli, and cauliflower.

In this system, The rules:
The explanation:

Gametophytic Self-Incompatibility (GSI)

This form of self-incompatibility is more common than SSI but not so well understood. It occurs in nearly one-half of all the families of angiosperms, including The rules: The mechanism:
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16 March 2001