Plant propagation techniques—Which method routinely employs girdling (ringing) as a step? Identify the propagation method in which a stem is partially girdled or wounded to induce adventitious roots while still attached to the parent plant.

Introduction / Context:
Several vegetative propagation techniques exist in horticulture. Girdling (ringing) the bark to interrupt phloem transport is a hallmark step in air layering, a form of layering used to induce roots on stems still attached to the mother plant.

Given Data / Assumptions:

• The method involves wounding or removing a bark ring.
• Rooting is encouraged at the wound site while the shoot remains attached.
• Moist medium (sphagnum/soil) is wrapped around the girdled area.

Concept / Approach:
Layering exploits the plant’s ability to form adventitious roots under hormonal and moisture cues. Girdling accumulates carbohydrates and auxins above the wound, improving rooting success. Once roots develop, the new plant is severed and potted.

Step-by-Step Solution:

Verification / Alternative check:
Standard horticulture manuals describe ringing/wounding specifically under layering, especially air layering (marcotting).

Why Other Options Are Wrong:

• Grafting/budding transfer a scion or bud to a rootstock; no rooting at a girdled site.
• Cuttings are detached first; girdling is not typical.
• Micropropagation is in vitro and does not use bark girdling.

Common Pitfalls:
Confusing wounding for cuttings with true girdling used to initiate roots while attached.

Final Answer:
Layering (e.g., air layering/marcotting)