CP B.1b: Asexual Propagation Notes (Cuttings)

Hook

• In the previous lesson, sexual propagation was discussed. Sexual propagation uses seeds produced by fertilization in plants; most plants are propagated from seeds.
• Questions to consider: Do you agree that most plants are propagated from seeds? Why or why not? Can you think of plants propagated without seeds? If not by seeds, what parts are used and how are they propagated?

Ignite

• After understanding the basics and the advantages/disadvantages of sexual propagation, we proceed to asexual plant propagation.
• What is asexual plant propagation?
  • A plant propagation method using a growing part of a plant other than its seeds to produce a new plant.
  • Also known as “vegetative reproduction”; multiplication of new plants does not involve the seed cycle.
  • Also termed “clonal propagation.”
• Like sexual propagation, asexual propagation has its own advantages and disadvantages.
• Table 1 (concept): advantages and disadvantages of asexual propagation.

Overview: Asexual Propagation (Cutting focused)

• There are different types of asexual plant propagation methods; they include vegetative propagation through cuttings of stems, leaves, and roots. Layering, budding, and grafting are other types (Hartmann et al., 2010).
• This learning guide focuses on cutting as an asexual propagation method.
• In cutting, different parts of the plant can be used. Historically, only select plants were propagated this way; advances have broadened its applicability.
• Time frame: $30\text{ minutes}$ (1 meeting).

Advantages and Disadvantages (Table 1)

• Advantages:
  • Plants mature in shorter time.
  • It bypasses the juvenile characteristics of a species.
  • It avoids the transmission of certain diseases.
  • It produces vigorous new varieties and hybrids.
• Disadvantages:
  • It could be time-consuming and expensive due to the need for specialized tools and skills.
  • It may increase the insect and disease susceptibility of plants due to the lack of genetic diversity found in seeds.
  • Some plants are patented, thus, making their propagation illegal.
  • It produces genetically identical offspring.
• Source note: Yashwantrao Chavan Maharashtra Open University (n.d.).
• In this guide, cutting is highlighted as a primary asexual propagation method; layering, budding, and grafting are other methods.

Main parts used for propagation through cutting

• 1) STEM (stem-cutting)
  • A common asexual propagation technique, well-suited for some home plants and herbs.
  • The new plant is genetically identical to the parent (a clone) because it is vegetatively propagated.
  • Tips for successful stem cuttings:
  • Sharpen all bladed tools for clean, precise cuts.
  • Sterilize tools and clean the cutting area.
  • Determine the node and include at least $1$ node (a node is a point along a plant stem where leaves or other stems are attached; an internode is the area between two nodes).
  • Cut a $4{-}6\text{ inch}$ piece of the plant stem or branch with a clean, slanted cut.
  • Dip cuttings in a rooting hormone solution or powder; use a rooting hormone with fungicide to speed root development and prevent root rot.
  • Cuttings should be taken in the morning when the plant has more moisture.
  • For most plants, dip the cut ends in water while waiting to plant to prevent embolism (air bubble blocking a xylem vessel).
  • Some plants (cacti/succulents) should be air-dried for a few hours before planting to avoid rotting.
  • Use sharp tools; tool type depends on stem/branch: scissors/shears for woody stems; blade/razor for succulent stems.
  • Rooting hormones promote root development, increase success rate, reduce time to root, increase root number per cutting, and improve uniformity.
  • If rooting powders/solutions are unavailable, a hone/whetstone can be used to stimulate root development in some species (Firth & Trask, 2017).
  • There are two main stem types: herbaceous (soft, succulent) and woody stems.
  • Herbaceous examples: mayana (Solenostemon scutellariodes), kamantigue (Impatiens balsamina), basil (Ocimum basilicum), parsley (Petroselinum crispum), spinach (Spinacia oleracea).
  • Figure reference: newly planted stem cuttings of mayana (Figure 1).
  • Woody stems include gumamela/Hibiscus rosa-sinensis, guava (Psidium guajava), avocado (Persea americana), San Francisco/Crotons (Codiaeum variegatum), mulberry (Morus alba), durian (Durio zibethinus), lanzones (Lansium parasiticum), rambutan (Nephelium lappaceum), lemon (Citrus limon), pili (Canarium ovatum).
  • Figure reference: woody stem ready for cutting (Figure 2).
• 2) LEAVES
  • Some plants can grow from leaves or leaf segments.
  • Examples: Katakataka (Bryophyllum pinnatum), Sampagita, snake plant (Sansevieria spp.), ZZ plant.
  • Leaf cutting: removal of a leaf blade (or leaf blade with petiole) and planting in prepared soil or water; the leaf or petiole develops roots and stems or small plantlets (Blazich & LeBude, 2018).
  • Some species require a leaf blade with the petiole.
  • Certain herbaceous plants (e.g., African violets, begonias, snake plants) can propagate from leaf segments that include some veins.
  • Figure reference: roots developed from the leaves of Zamioculcas sp. (welcome plant) (Figure 4).
• 3) ROOTS
  • Some plants can be propagated from roots, typically woody species.
  • Roots near the crown are used; roots are cut into $2{-}6\text{ inch}$ segments and planted to develop shoots from the root.
  • Examples: raspberry, rose, fig.
  • Figure reference: bagawak/starburst Clerodendrum quadriloculare propagated from roots (Figure 5).

Practical notes on propagation from roots and weeds

• Plants that regenerate from roots are often hard to control; some common weeds regrow from roots (e.g., dandelions, Siam weed, dilang-aso). When weeding, ensure roots are completely removed to prevent regrowth.

Application: local plants and a simple exercise

• Activity: determine which local plants could be propagated through cuttings.
• Nature of exercise: GRADED exercise (20 points) to build familiarity with surrounding plants.
• Task: Complete table — For each plant, indicate Yes/No for propagation by cuttings and, if yes, which part of the plant is used.
  • Plants listed: Camote/sweet potato (Ipomoea batatas); Cassava (Manihot esculenta); Cabbage (Brassica oleracea var. capitata); Mustard (Brassica juncea); Radish (Raphanus sativus); Mung bean (Vigna radiata); Sugarcane (Saccharum officinarum); Oregano (Origanum vulgare); Rosemary (Rosmarinus officinale); Lima bean (Phaseolus lunatus).
• Time allowance: $8\text{ mins}$.

Weeds and practical propagation notes

• Root-based regeneration is common in certain weeds; effective weed control requires removing roots.
• Asexual propagation can be advantageous for producing uniform plants rapidly, but genetic diversity is reduced, which can affect disease resistance and adaptability.

Summary connections to broader concepts

• Asexual propagation (cutting) provides cloning of desirable cultivars, preserving specific traits.
• Compared to sexual propagation, it bypasses seed production and fertilization, leading to rapid establishment of new plants.
• Ethical and legal considerations include patented cultivars where propagation may be restricted or illegal.
• Practical considerations include using sterile tools, correct cutting length, timing of cuts (morning moisture), and proper use of rooting hormones to speed root development.

Roots, leaves, and stems: quick reference

• Stem-cutting: $4{-}6\text{ inch}$ segments; include at least $1$ node; stay mindful of internodes; use rooting hormone with fungicide; avoid embolism by keeping ends hydrated until planting.
• Leaf-cutting: leaf blade or leaf with petiole; roots and plantlets form from leaf segments; examples include Bryophyllum, African violets, Begonias, Sansevieria, etc.
• Root-cutting: $2{-}6\text{ inch}$ root segments; used for species like raspberry, rose, fig; important for certain woody plants.

References (as cited in the guide)

• Blazich, F. & LeBude, A. (2018). North Carolina extension gardener handbook. NC State Extension Publications.
• Firth, C.S. & Trask, A. (2017). Honey as an alternative rooting stimulant for cutting. University of Hawai'i at Manoa.
• Hartmann, H., Kester, D., Davis, F. Jr., & Geneve, R. (2010). Hartmann & Kester's Plant Propagation: Principles and Practices (8th ed.). Pearson.
• Sorensen, D.C. & Garland, K. (n.d.). Plant Propagation. University of Maine Cooperative Extension.
• Yashwantrao Chavan Maharashtra Open University. (n.d.). Resource Book on Horticulture Nursery Management.