Asexual Propagation in Plants, Types and Examples

Asexual Propagation in Plants:

Asexual propagation in plants is defined as the breeding of a specific plant specimen through natural processes by taking a vegetative part of the parent plant or stock.

Asexual Propagation is also referred to as vegetative propagation or asexual reproduction since a vegetative part of the plant (that is; root, stem, or leaf) is taken and made to regenerate itself into a new plant. The resulting plant that forms from this process is termed a clone of the parent plant.

A clone in this instance of asexual reproduction refers to a genetically identical offspring to it’s parent plant. For this reason, pollen grains and egg cells (which are associated with the plant's sexual reproduction) are not required in clone formation.

You can read on sexual propagation in plants here.

Clone formation is the best way to retain some plant species, especially the best of their kinds.

Types of Asexual Propagation

Various techniques are used to bring about vegetative propagation (or plants' asexual reproduction). They include:

1. Grafting

Grafting requires that a part of the parent plant is cut off and joined to another rooted plant so that they can grow as one plant.

The image below shows the the process of grafting:

The term scion refers to the branch of the cut plant (desired variety) that will be grafted to the other rooted plant. Such rooted plant is called the stock. In this regard, grafting is done on a stock plant, with a very strong root system.

Please read on agricultural terms and their meanings here.

Grafting can be achieved through various methods: Some of these include:

• Wedge Grafting

• Cleft Grafting

• Tongue Grafting

• Bark Grafting

• Butt Grafting

• Side Grafting

2. Budding

Budding is a type of grafting. In fact, It is also called bud grafting.

The major difference between budding and grafting has to do with the shape on the stock on which the scion is inserted.

In budding, the part of the stock in which the scion is inserted is cut in a 'T shape'.

The image below shows an instance of budding:

The scion is inserted into the T shaped stock. The cut is then covered by winding a strip of polythene sheet, keeping only the bud exposed.

We have different types of budding. They include:

• Chip Budding

• Patch Budding

• T-budding

You can read on the reproductive differences between gymnosperms and angiosperms here.

3. Cuttings

In cuttings, a part of the parent plant is severed (cut away) and planted. After some time, the severed part regenerates into a new plant. The image below shows this:

Cuttings are categorized into different types depending on the part of plant severed. They include:

• Stem cuttings: The stem of a plant is severed and planted. For example mint and dahlia plants.
• Root cuttings: The root of the plant is severed and planted. Examples are breadfruit and white poinsettia plants.
• Leaf cuttings: A part of the plant's leaf is cut and planted. Examples are the african violets and kalanchoe plants.

You can Attempt Len Academy questions on agric science here.

4. Layering

This technique of vegetative propagation is similar to stem cuttings. The difference is summarized in the quote below:

In normal stem cuttings, the stem (not having roots) are cut away from the parent plant before it is planted.

In layering, the stem is first allowed to develop roots. These roots must be formed on the stem of the mother plant for layering to occur. Only after the formation of the root can we cut off the stem and plant it.

Below is an image showing the process of layering:

We have different types of layering. They are:

• Air Layering

• Mound (stool) Layering

• Compound Layering

• Tip Layering

• Simple Layering

Please read on anatomical and structural differences between gymnosperms and angiosperms here.

5. Separation

Separation applies to plant that produce corms and bulbs.

During separation, the new shoot (part of the plant above the root) is first detached (or separated) from the parent plant before it is planted. The bulbs of tulip and lily plants can be separated in this way.

The image below shows the process of separation:

Note: Certain bulbs may also produce smaller bulbs termed bulblets. The bulblets are always attached to the base of the parent bulb and can be easily separated in order to bring about vegetative propagation.

Please read on the differences between plants and crops here.

Another instance of separation is seen in cormels. The cormels refer to little or baby corms that attach to the parent corm, and these can also be separated for the purpose of vegetative propagation.

5. Division

Division is quite different from separation. In division, different parts of the plant (having buds) is divided into two or more parts (or sections). Each of the section is then planted to produce an independent plant.

Examples of plants the can be propagated via division are the rhizomes of iris and lily plants. Also, stem tubers like yams and potatoes with the presence of buds in various sections can also be propagated through division.

Below is an image of Kangaroo Paw Rhizome that had undergone division:

Division is generally used in asexual propagation when a cluster of plants are cut away into small units. When planted, the isolated units will grow into a parent plant.

You can Attempt Len Academy questions on agric science, JSS1 here.

Always understand that the process of division (in asexual propagation) does not occur naturally.