Asexual Propagation

Asexual Propagation

– controlled perpetuation of plants.Its objective is to achieve anincrease in number to preserve theessential characteristic of a plant.

Reasons/Importance

–Production of true to type plant (genetically identical)

–Propagation of plants that does not generally produce seeds (breadfruit)

–Propagation of plants that produce seed but are difficult to germinate (banana, abaca)

–Shorter maturity period of plants/early bearing

–Production of uniform asexual rootstock

Characteristics of a good rootstock

• good root system

• resistant to soil-borne-disease

• resistant to drought

Methods of asexual propagation

• Cutting – propagation technique where in a vegetable parts is detached/removed from the mother plant and is subjected to a condition favorable for the regeneration of roots and production of shoots.

• Air layering/marcotting – adventitious roots are caused to form on stem while still attached to the mother plant.

• Garfting – art of connecting or joining two plant parts and allowing it to unite and grow as one plant.

• Budding – a form of grafting where in the scion is limited only to a single bud.

Air Layering

• Principle of air layering/marcotting

Restricting the flow or interruption of thedownward movement of organic materials(CHO, growth regulators and other growthfactors) synthesized from the leaves andgrowing shoot tips, accumulating thosematerials above the wound therebystimulating rooting.

Advantage of Marcotting over Cutting

• Stress avoidance – treated branch is still supplied with water and nutrients by the mother plant.

• Disadvantages:

– Requires more skill

– Needs more time

– More complicated

– Requires other materials

Factors affecting rooting of layered plants

• skill of the propagator – branch selection• removal of the cambium layer (composed of actively

dividing tissues) which when not completely remove will regenerate to phloem vessels or re-growth of the bark.

• condition of the mother plant (vegetative stage)• rooting medium – characteristics of a good rooting

medium: a) good aeration, b) good moisture supply, c) able to supply nutrients

• wrapping materials – to prevent moisture loss, must be transparent, stable and strong

• treatment – growth regulators e.g. ANAA, IBA, IAA

Plant cell characteristics that make propagation by cutting possible

Totipotency – a plant cell characteristic by which a single living vegetative cell contains all the genetic information needed to regenerate an entire plant.

Dedifferentiation – a plant cell characteristics by which a mature or differentiated cell could return back to meristematic condition.

Materials Needed

• rooting medium – create an environment similar to the soil (dark environment, moisture, nutrient, aeration).

• cellophane – any transparent material for the ease in checking emerging shoots

• a good and healthy mother plant• tying material• sharp knife or cutter• root inducer (for difficult to root and expensive

planting material).