Asexual propagation = production of new plants without use of seeds

1. Asexual propagation • Asexual propagation = production of new plants without use of seeds • Why use asexual propagation? • Easier or cheaper to propagate than seed (e.g. potato) • Able to produce uniform plants (clones) • Some plants do not produce seeds (e.g. navel oranges) • Shorter time in juvenile stage (e.g. fruit trees) • Able to incorporate new characteristics into plant (e.g. European grapes, dwarf fruit trees) • Create ‘self-pollinating’ varieties to save space (e.g. 3-in-1 fruit trees)

2. Today Wednesday Asexual propagation • Division • Major types of asexual propagation: • Cuttings • Layering • Grafting • Budding • Micropropagation (tissue culture)

3. Orchids (separate pseudobulbs) Asexual propagation • Division = Separating plants by tearing apart roots, rhizomes or stolons • Common technique for multi-stem plants such as: • Ferns (rhizomes) • Iris (rhizomes) • Houseplants with rhizomes or roots (e.g. Sansevaria, African Violets, Aloe) • Spider plants (remove plantlets at ends of stolons)

4. Asexual propagation • Cuttings = production of new plants from pieces of stem, leaves, roots or buds • Common method of propagation • Types of cuttings: • Leaf cuttings • Leaf-bud cuttings • Stem cuttings • Root cuttings

5. Asexual propagation • Advantages: many leaves/plant; few stock plants needed • Leaf Cuttings : • Disadvantage: most plants cannot produce adventitious shoots from leaves • Types of leaf cuttings: • Leaf-petiolecutting: entire leaf propagated • Plantlet forms at base of petiole • Use for African Violets, Begonia, Peperomia

6. Asexual propagation • Types of leaf cuttings: • Leaf Cuttings : • Leaf-bladecutting: just leaf blade propagated • Plantlet forms at base of leaf • Use for jade and some succulent plants • Leaf-veincutting: perpendicular slits cut in veins of leaf • Plantlets form at each slit • Use for some Rex Begonia species

7. Asexual propagation • Types of leaf cuttings: • Leaf Cuttings : • Leaf-sectioncutting: portion of leaf blade propagated • Plantlet forms at base of cutting • Use for Sansevaria (variegation will not reproduce) or Rex Begonia

8. Asexual propagation • Leaf-budCuttings: stem section with 1-2 lateral (axillary) buds propagated • Used to obtain many cuttings from plants whose leaves do not form adventitious stems • Axillary bud becomes plantlet • Use for houseplants such as Philodendron, Pothos, rubber tree and for some large-leaved shrubs (e.g. Rhododendron)

9. Asexual propagation • for plants whose leaves do not form adventitious stems • StemCuttings: portion of stems propagated • Types of stem cuttings: • Herbaceouscutting: stems from nonwoody plants (most houseplants such as Coleus, Poinsettia, corn plants) • Softwoodcutting: new, soft stems taken from woody plants in Spring (e.g. Lilac, maple, dogwood) • Semi-hardwoodcutting: partially mature wood on current-season stem in Summer (e.g. Rhododendron, Citrus trees) • hardwoodcutting: mature stems • Taken from deciduous plants in late Fall to early Spring when dormant • Taken from evergreen plants in late Fall to late Winter when dormant

10. Asexual propagation • Used to obtain cuttings from plants whose leaves do not form adventitious stems • RootCuttings: root section propagated • Roots store food reserves at end of growing season; root cutting most effective late Winter to early Spring • Use for houseplants with rhizomes and many woody shrubs (e.g. Rubus) • Most cuttings more successful if: • high humidity, sanitary techniques, • use rooting hormones (IBA or NAA), • inserted properly, correct rooting medium, addition of bottom heat and taken at correct time of year

11. Asexual propagation • Layering = formation of adventitious roots without cutting the plant • Two common types: • Airlayering: wound stem, surround stem with moist sphagnum moss and wrap with polyethylene • Used for houseplants (e.g. rubber trees, corn plants) and woody plants (e.g. Cornus, Rhododendron) • Tiplayering: stems of ‘mother’ plant buried in soil to promote growth of adventitious roots • Used for houseplants (e.g. Pothos) and many woody shrubs (e.g. Rhododendron, Forsythia, Rubus)