- It is one of the artificial methods of asexual reproduction.
- In this method, the roots are developed on the stem while the stem is still attached to the parent plant.
- This method is commonly used in jasmine, magnolia, strawberry, raspberry, etc.
- Many plantlets can be produced in a short period of time.
- It is induced artificially by bending the branch to the ground and covering it with the moist soil.
- The apical part of the stem produces leaves whereas the underground part produces the roots.
- Later the layered branch is separated from the parent plant.
Types of layering
- Layering can be done by various methods.
- Some common methods of layering are given below:
A) Simple layering
- In this method, a low growing stem of more than one year age is bent downward and the target region is buried in the soil.
- A few inches of the leafy stem must remain above the ground for the bent stem to grow into a new plant.
- The buried portion of the stem develops roots after 2-3 months when watered regularly.
- When the stem develops roots, it is separated from the parent plant and kept in nurseries.
- Plants like lemon, citrus, etc. are propagated by this method.
B) Compound layering
- The entire low growing stem is bent downward and buried in the soil in this method.
- Its tip should be out of the soil.
- The stem should be watered regularly so that the nodes produce new plantlets.
- This method is commonly applied in apples, pears, walnuts, etc. to produce many plantlets in a short period of time.
C) Tip layering
- The tip of the stem of a plant is buried in the soil to develop new plants in this method.
- About a 5 to 8 cm long tip of the stem is buried in the soil and watered regularly.
- When the tip develops roots, the portion of the stem is separated from the parent plants after 3-4 months.
- This method is commonly applied in raspberry, blackberry, etc.
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D) Mound or stool layering
- Ground layering, or mound layering is the typical propagation technique.
- The original plants are set in the ground with the stem nearly horizontal, which forces side buds to grow upward.
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- After this, the original stem is buried up-to 20 to 25 cm from the ground.
- At the end of the growing season, the side branches will develop roots and can be separated after one year.
- The target region of the stem is wounded or a strip of bark is removed and then encased in a moisture retaining medium, such as a moss or cloth.
- It is further surrounded in a moisture barrier such as a plastic film.
- Rooting hormone i.e. IBA(Indole -3- butyric acid) is often applied to encourage the growth of roots.
- The wounded portion develops roots within 4-8 weeks.
- Then, the portion is separated from the parent plant and planted.
- Air layering is the most popular method of artificial vegetative propagation.
Layering and its types