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  • Количество слайдов: 11

Effect of polarity on rooting • stem cuttings form shoots at the distal end, Effect of polarity on rooting • stem cuttings form shoots at the distal end, roots at the proximal end • auxin always moves from shoot tip to base (no matter the stem orientation)

Effects of buds and leaves on rooting • “active” buds promote rooting, dormant buds Effects of buds and leaves on rooting • “active” buds promote rooting, dormant buds have no effect • leaves exert a strong stimulatory influence (both carbohydrates and auxin are translocated from leaves)

Effect of wood “type” on rooting of woody cuttings • Seedling (genotype) differences (Norway Effect of wood “type” on rooting of woody cuttings • Seedling (genotype) differences (Norway spruce, white pine, red maple) • lateral shoots usu. better than terminals – beware plagiotropic growth of laterals • basal and medial shoot portions are usu. better than terminals • flowering wood is slower than vegetative • heel cuttings are better for some spp. (quince, narrowleaved evergreen spp)

Seasonal timing (when cuttings are taken) can affect rooting of woody cuttings • hardwood Seasonal timing (when cuttings are taken) can affect rooting of woody cuttings • hardwood cuttings with resting buds are best • softwood cuttings are usu. best from the first flush • narrow-leaved evergreens are best taken from late fall to late winter • broad-leaved evergreens (e. g. , olive cuttings root best when taken during late spring, poorest when taken in midwinter)

Cold storage of rooted and unrooted leafy cuttings • • Several days to several Cold storage of rooted and unrooted leafy cuttings • • Several days to several weeks (for convenience) Temperature near 40 o F (4 o C) for temperate spp. High RH Pathogen control

Handling field-propagated woody cuttings (after rooting and lining out) • bare-root nursery stock - Handling field-propagated woody cuttings (after rooting and lining out) • bare-root nursery stock - deciduous shrubs, trees • balled-and-burlapped (B & B) stock - broad- or narrowleaved evergreen spp. • container production - is rapidly replacing field production – – easier handling improved marketability better cultural control faster product turnover • newer alternatives - pot-in-pot, grow bags, etc.

Pathogen/pest management in propagation • Pests (insects, mites, nematodes, weeds) • Pathogens (fungi, bacteria, Pathogen/pest management in propagation • Pests (insects, mites, nematodes, weeds) • Pathogens (fungi, bacteria, viruses) • Goals: – to keep stock plants and propagules as clean and pest-free as possible – identification, indexing of systemic pathogens

Pathogen identification methods • • • visual inspection - specific symptoms culture indexing - Pathogen identification methods • • • visual inspection - specific symptoms culture indexing - systemic bacteria, fungi virus indexing (e. g. , indicator cultivars) serological tests (e. g. , ELISA tests) biochemical/molecular methods (e. g. , specific viral RNA patterns on a gel)

Methods of pest/pathogen management in propagation • preventive measures (e. g. , clean stock, Methods of pest/pathogen management in propagation • preventive measures (e. g. , clean stock, use of cultivar resistance, scouting) • integrated pest management (IPM) – chemical control (e. g. , quantity control, rotation) – biological control (the fungus Gliocladim virens instead of fungicidal control of Rhizoctonia and Pythium damp-off) – cultural control (e. g. , sanitation, healthy stock plants, heat pasteurization of propagation medium)

Aphid control - a case study of IPM used in a propagation house • Aphid control - a case study of IPM used in a propagation house • microscreens on vents/doorways of propagation houses • scouting (e. g. , yellow sticky cards) • use of a natural predator (the midge Aphidoletes aphidimyza) • natural pyrethrin insecticides (for populations too large for cultural, biological control) • use of insect growth retardants (Enstar II specific to immature aphids) • careful use (and rotation) of more toxic insecticides

Best management practices (as applied to nursery and greenhouse plant propagation) • a set Best management practices (as applied to nursery and greenhouse plant propagation) • a set of practices voluntarily adopted by nurseries and greenhouses to control irrigation and fertilization • includes: – – collecting run-off water when injecting fertilizer applying fertilizer only to obtain a growth response monitoring the quantity of irrigation (to prevent overwatering) recycling run-off water where feasible