Plant Propagation and Nursery Management
Domain 7 tests how plants are multiplied and how nursery stock is raised, hardened and sold true-to-type.
Sexual versus asexual
- Seed propagation is cheap and used for papaya, marigold and tomato; it carries variability.
- Asexual methods keep cultivar characters: cuttings, layering, grafting, budding, suckers, division, tissue culture.
Methods and examples
- Stem cuttings: rose, bougainvillea; hardwood, semi-hardwood and softwood types.
- Air layering: guava, litchi, pomegranate.
- Grafting: mango (stone grafting, veneer), citrus, sapota.
- Budding: patch and T-budding in rose and citrus.
- Suckers: banana, pineapple; offsets: chrysanthemum.
Worked example
Air layering of litchi: choose a healthy pencil-thick shoot, remove a 2-3 cm ring of bark below a node, treat with IBA at 2000-5000 ppm, wrap moist sphagnum moss in polythene and keep it moist. Reasoning: ring-barking breaks phloem and cambium continuity, so photosynthates accumulate above the cut and, with auxin, induce adventitious roots; moss supplies moisture and polythene prevents desiccation. Roots appear in 4-8 weeks, then the layer is severed and potted.
Marks-losing traps
- Confusing budding with grafting.
- Taking scion wood from a diseased or juvenile tree.
- Skipping hardening before field planting.
- Using a rootstock incompatible with the scion.