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 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 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, narrow-leaved evergreen spp)

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 weeks (for convenience) Temperature near 40o F (4o C) for temperate spp. High RH Pathogen control

bare-root nursery stock - deciduous shrubs, trees 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 narrow-leaved 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, 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 - 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, 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 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 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