CH Plant Propagation 2 — Questions and Answers
Question 1: Air layering is a propagation method best suited for:
- Propagating fine-rooted annual species
- Rooting a stem while still attached to the parent plant (Correct answer)
- Producing seedlings under grow lights
- Separating bulb offsets
Correct answer: Rooting a stem while still attached to the parent plant
Air layering wounds a stem on the parent plant, packs the wound with moist sphagnum, and wraps it to encourage roots to form before the new plant is severed.
Question 2: Division as a propagation method is most commonly applied to:
- Trees with deep taproots
- Clump-forming perennials and ornamental grasses (Correct answer)
- Annual vegetables
- Tropical woody species
Correct answer: Clump-forming perennials and ornamental grasses
Division splits clump-forming perennials and grasses into multiple rooted sections, rejuvenating crowded plants and quickly producing several new plants identical to the parent.
Question 3: In seed propagation, the term 'germination percentage' refers to:
- The percent of seeds that produce male flowers
- The proportion of seeds in a lot that successfully germinate under optimal conditions (Correct answer)
- Moisture content of stored seed
- Percentage of seeds treated with fungicide
Correct answer: The proportion of seeds in a lot that successfully germinate under optimal conditions
Germination percentage indicates seed lot viability and is used to calculate seeding rates; a lower percentage means more seeds must be sown to achieve the desired plant stand.
Question 4: Which grafting method is commonly used for top-working (reworking) established fruit trees with new scion wood?
- Splice grafting
- Cleft grafting (Correct answer)
- Budding (T-budding)
- Approach grafting
Correct answer: Cleft grafting
Cleft grafting is used to graft scion wood onto large-diameter stubs of established trees, making it the standard method for top-working fruit trees to new varieties.
Question 5: A propagation mist system benefits stem cuttings primarily by:
- Delivering fertilizer to cuttings
- Maintaining high humidity to reduce transpiration water loss before roots form (Correct answer)
- Cooling the rooting medium to 50°F
- Eliminating the need for rooting hormone
Correct answer: Maintaining high humidity to reduce transpiration water loss before roots form
Intermittent mist keeps cutting foliage wet, reducing stomatal moisture loss and preventing wilting while the cutting is rootless and unable to replace water through uptake.
Question 6: Hardwood cuttings of deciduous shrubs are typically taken and propagated during which season?
- Mid-summer during active growth
- Late fall to early winter during dormancy (Correct answer)
- Early spring at bud swell
- Midsummer after bloom
Correct answer: Late fall to early winter during dormancy
Hardwood cuttings are made from fully lignified, dormant wood in late fall or winter, then stored or stuck in media where they slowly root during winter and spring.
CH Plant Propagation 2
Air layering is a propagation method best suited for: