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This section is about the outbreeding device concept and the relationship between pollen pill interaction and outbreeding.
Before we get to the outbreeding device types, let’s first understand what outbreeding is.
Meaning of Outbreeding Devices
Outbreeding devices refers to the processes or mechanisms that plants use to avoid self-pollination.
These devices are used by plants, but why? These are the reasons.
The Outbreeding Mechanism
- Inbreeding Depression: This is because plants can become depressed from inbreeding
- There are no genetic variations in self-pollinating, because the same genes of males as females exist
- Unisexuality: Outbreeding is the only option if the plant is not unisexual
- Unsynchronised pollen release: For breeding to occur, it is important that the release of pollen grains as well as the receptivity for stigma be synchronised. This will prevent self-pollination
Let’s now get to the main topic: the types of outbreeding devices.
Outbreeding devices
The plants can use a variety of devices to encourage cross-pollination. These are listed below.
Unisexuality: This is an Outbreeding technique in which the plant bears either male or female flowers. The flower is not hermaphrodite. This is also known as dioecism.
Dichogamy: The maturity time of the stigma and anther in this outbreeding device is different. Dichogamy can therefore be divided into two types depending on the maturity.
- Protandry -The androecium is matured before the gynoecium. Maize plants, for example
- Protogyny – The gynoecium matures prior to the androecium
Herkogamy: Herkogamy refers to a condition that occurs naturally and prevents pollen grains from entering the ovaries.
Self-Sterility: This is a trait that prevents the pollen grains from germinating. The ovule and grain contain the self-sterile gene.
Heterostyly: In this Outbreeding device the levels of the stigma and anther are different, which prevents the pollen grain from reaching the stigma and pollinating the stigma.
Pollen Prepotency is a condition in which a different flower’s pollen matures quicker than the one of the same flower. This helps to prevent autogamy.
