PLANT PROPAGATION

1. SEXUAL PROPAGATION

• This involves multiplying plants by using seeds.

Advantages

• Seeds are cheap and easy to handle.

• Easy to sow and prepare for planting.

• Easy to store without losing quality or quantity.

• Seeds remain viable for a long time if stored well.

• Can be sown mechanically using seed drills.

• Less risk of passing diseases from parent to offspring.

• Only method for propagating crops that cannot be grown vegetatively.

• Seeds can produce plants different from parents, which helps in crop improvement.

Disadvantages

• Can cause variation and off-types in offspring.

• Plants take longer to bear fruit (long juvenile period).

• Needs proper site preparation before sowing.

2. ASEXUAL PROPAGATION

• Also called vegetative propagation.

• It involves producing new plants without using seeds.

Vegetative Planting Materials

• Cuttings: Stem parts used to grow new plants (e.g. cassava, sugarcane).

• Runners: Horizontal stems growing on the ground (e.g. sweet potatoes, star grass).

• Stem tubers: Swollen underground stems (e.g. Irish potato).

• Suckers: Shoots from the base of a plant (e.g. bananas, pineapples).

• Bulbs: Fleshy underground leaves (e.g. onions, garlic).

• Corms: Swollen underground stem bases.

• Rhizomes: Thick horizontal underground stems (e.g. bamboos).

• Layering: A branch is pegged to the ground to grow roots while still attached.

• Budding: A bud from one plant is joined to another to grow a new shoot.

• Grafting: A scion (upper part) is joined to a stock (lower part) to combine qualities.

Advantages of Asexual Propagation

• Shorter time to produce fruit.

• No dormancy period as in some seeds.

• Produces genetically identical plants to the parent.

• Can be used for plants whose seeds are not viable.

• More resistant to environmental stress than seedlings.

• Has food reserves to support early growth.

• Planting materials are readily available from previous crops.

Disadvantages of Asexual Propagation

• Diseases can easily be passed to new plants.

• No variation, making it hard to improve crops.

• Bulky and harder to transport than seeds.

• Some methods require special skills or training.

Techniques of Vegetative Propagation

1. Layering

Definition:
Layering is a method where a branch of a plant is bent down and pegged to the ground while still attached to the parent plant so that it develops roots and grows into a new plant.

Procedure:

• Select a healthy and flexible branch of the plant.

• Bend the branch down to the ground.

• Remove leaves from the part that will be buried.

• Wound the lower side of the branch slightly (optional but speeds up root formation).

• Bury the wounded part about 5–10 cm into the soil, leaving the growing tip above ground.

• Peg or tie the buried part firmly with a stick or wire to keep it in the soil.

• Water regularly to keep the soil moist.

• After a few weeks, roots will develop from the buried section.

• Once the new roots are well-formed, cut the branch from the parent plant.

• Transplant the new plant to a desired location.

2. Budding

Definition:
Budding is the process of inserting a single bud from one plant into the stem of another plant so that it grows into a new shoot.

Procedure (T-budding method):

• Choose a healthy bud from the desired plant (called the donor).

• Cut the bud with a small part of the bark (this is called a bud shield).

• Select a suitable stem of the plant to receive the bud (called the rootstock).

• On the rootstock, make a T-shaped cut on the bark.

• Carefully open the flaps of the T-cut using a knife.

• Insert the bud shield into the T-cut so that the bud fits tightly.

• Wrap the area with budding tape or polythene strip to hold the bud in place.

• After about 2–3 weeks, if the bud is green and healthy, remove the tape.

• When the bud begins to grow, cut off the top part of the rootstock above the bud to allow the bud to grow into the new shoot.

3. Grafting

Definition:
Grafting is the process of joining a scion (a shoot or twig) from a desired plant onto the rootstock of another plant so they grow as one.

Procedure:

• Select a healthy rootstock and a matching scion (should be of the same size for best results).

• Cut the top of the rootstock with a clean, slanting cut.

• Make a matching slanting cut on the base of the scion.

• Fit the two cut surfaces tightly together, ensuring the cambium layers (growing tissue just under the bark) are in contact.

• Wrap the joint securely with grafting tape or polythene to hold the scion in place and prevent drying.

• Cover the grafted area to retain moisture and protect from pests or diseases.

• After a few weeks, if successful, the scion will start to grow.

• Once it starts growing well, remove the tape and care for the new plant as normal.