PLANT PROPAGATION

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PLANT PROPAGATION

• Introduction to Horticulture

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INTRODUCTION

• Propagation or Reproduction is simply the process
  of increasing the numbers of a species.
• Two types of propagation are sexual and asexual.

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INTRODUCTION

• Sexual Reproduction is the union of an egg
  (ovule) and sperm (pollen), resulting in a seed.
  
• Asexual Reproduction uses a vegetative part of
  only one parent plant.

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ADVANTAGES OF SEXUAL PROPAGATION

• Less expensive cost of seed
• Requires little skill
• For some plants, it is the only way to propagate
  them
• Avoids passing on some diseases
• Hybrid Vigor is when offspring inherits the good
  traits of both parents

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ADVANTAGES OF ASEXUAL PROPAGATION

• Produces a plant quicker
• Plants are identical to parent plants
• Guaranteed product
• In some species, it is the only way to propagate
  them

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SEXUAL PROPAGATION

• Seed production is done in dry climates to reduce
  plant disease problems
• Harvesting and collecting seeds must be done
  gently to reduce seed damage
• Cleaning seeds is important to seed quality
• Dry fruit seeds are easily threshed from pods or
  capsules
• Fleshy fruit seeds are more difficult as seeds
  are washed and dried once removed
• Storing of seeds requires cool temperatures to
  prevent germination
• Some require moist storage, others dry, some
  dont store

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SEXUAL PROPAGATION

• Testing and labeling of seeds are bound by
  federal and state laws
• Seeds are tested for
• Certification or trueness of name, based on
  parent traits
• Origin or place grown
• Germination percentage or amount of viable seeds
• Pure seed percentage
• Percentage of other ingredients

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SEXUAL PROPAGATION

• Typical Certified Seed Label
• Origin
• Germination
• Purity
• Other Ingredients
• Must be present for sale and shipment of seed

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SEXUAL PROPAGATION

• Parts of a Seed

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SEED GERMINATION

• Germinate means to grow or sprout
• Germination is dependent upon
• Moisture
• Temperature
• Air
• Light
• Medium

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SEED GERMINATION

• Moisture
• Seeds must imbibe or absorb moisture to soften
  the seed coat and stimulate growth
• Temperature
• Different seeds require different temperatures to
  trigger the growing process
• Air
• When viable seeds begin to grow, the cells of the
  seed start the process of respiration which
  requires oxygen

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SEED GERMINATION

• Light
• Some seeds require light to grow and some seeds
  are inhibited by light
• Medium
• A suitable growing medium can be soil, peat moss,
  or other organics
• The most important trait is good seed to soil
  contact
• Should be firm and moist

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SEED GERMINATION

• Dormancy is when little or no activity is
  happening in plants or seeds
• Some seeds need help overcoming this dormancy
• Scarification overcomes seed coat dormancy
• Mechanical scraping, sanding, gouging of seed
  coat
• Sometimes done chemically by digestion of animals
• Stratification overcomes embryo dormancy
• Chilling period in cool moist environment
• Many trees seeds require this winter simulation

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SEED GERMINATION

• Indirect Seeding is planting in a greenhouse
  where conditions are easily controlled
• Plants are transplanted later to where they will
  complete their life cycle
• Damping-off is common among seedlings where
  fungal disease causes the plant to rot at the
  soil line
• Harden-off is the process of helping plants
  adjust to the outdoors by reducing the
  temperature gradually for weeks before
  transplanting

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SEED GERMINATION

• Direct Seeding is seeding where the plant will
  complete its life cycle considering
• Site Selection
• Seedbed Preparation
• Planting Date
• Planting Depth and Spacing
• Moisture

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SEED GERMINATION

• Site Selection
• Sunlight and soil drainage are two important
  factors
• Seedbed Preparation
• Soil should be firm, yet particles small enough
  to provide seed-to-soil contact
• Soil too loose or fine will erode or compact to
  reduce plant growth
• Planting Date
• Check local average last frost dates and plant
  after that
• About May 20th for our area (USU Extension)

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SEED GERMINATION

• Planting Depth and Spacing
• Depth rule of thumb is about twice the width of
  seed
• Ex Corn seed 3/8 wide-plant 3/4 deep
• Spacing is dependent on mature plant size
• Close spacing means more plants that compete
  resulting in lower production
• Distance wastes space and allows weeds to grow
• Moisture
• Soil should be moist but not wet
• Wet soil lacks oxygen and suffocates seed
• Soil ball test

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ASEXUAL PROPAGATION

• The production of plants using the vegetative
  parts of other stock or parent plants
• The resulting plant is an exact clone with the
  same DNA
• Used to ensure the same product as previous
  generations with no chance for crossing
• Can give growers a shorter growing period
  resulting in more profit
• Also used in species that require exacting
  conditions to germinate seeds

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ASEXUAL PROPAGATION

• Cutting is the most common and simplest method of
  asexual propagation
• The cutting, or part of the plant that is
  removed, is placed in growing media
• Roots form and individual plant develops with
  roots, stem, leaves and flowers.
• Four main types stem cuttings, leaf cuttings,
  leaf-bud cuttings, and root cuttings.

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ASEXUAL PROPAGATION

• Stem Cuttings
• Herbaceous cuttings come from plants without wood
  like geraniums
• Softwood cuttings are taken from new spring
  growth and require care
• Hardwood cuttings are taken during dormancy from
  1-year old growth

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ASEXUAL PROPAGATION

• Leaf Cuttings
• Leaf blade and petiole placed in medium
• Usually used on houseplants
• Some varieties require vein cuts to stimulate
  root growth

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ASEXUAL PROPAGATION

• Leaf-Bud Cuttings
• Leaf blade, petiole, and short piece of stem with
  a bud are cut and put in medium
• New bud provides growth and roots form on stem

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ASEXUAL PROPAGATION

• Root Cuttings
• Root pieces are planted in medium
• Must be cleaned and treated with fungicide
• Plant horizontally or vertically
• If planting vertically, avoid planting
  upside-down
• Cut top of root or closest to crown of plant with
  straight cut, bottom of root with a slant cut
• Commonly used on raspberries or plants that
  produce suckers

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ASEXUAL PROPAGATION

• Caring for Cuttings
• Timing and Collecting at the proper time of year
  is critical to success
• Preparation of cuttings varies with species but
  many times wounding or scraping plant stimulates
  root growth
• Providing a root-inducing environment is
  important
• Use good media that is moist but not too moist
• Indirect sun prevents drying out of cuttings
• High humidity reduces transpiration rates

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ASEXUAL PROPAGATION

• Grafting is the process of connecting two plant
  parts together so they will unite and grow as one
  plant
• Usually only used on woody plants
• Scion is the part of the new plant, usually the
  top portion containing the desired genetics
• Rootstock is the bottom that provides the root
  system for nutrient and water absorption
• Usually done during the dormancy period of trees
• Three main types Whip-and-Tongue, Cleft, and Bark

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ASEXUAL PROPAGATION

• Whip-and-Tongue Grafts
• Both scion and rootstock are the same diameter
• Usually done when under 1-inch in diameter
• Many fruit trees are done this way

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ASEXUAL PROPAGATION

• Cleft Grafts
• Small scions are grafted to larger rootstocks
• Must be careful to match up the cambium layers
• Used when rootstock is more mature such as
  damaged trees

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ASEXUAL PROPAGATION

• Bark Grafts
• Similar to a cleft graft where rootstock is
  larger
• Done in early spring when bark separates easily

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ASEXUAL PROPAGATION

• Budding is similar to grafting except that the
  scion is only a single bud
• Budding accomplishes the same purpose as grafting
  
• All growth from that point will be genetically
  the same as the bud
• Done in the early spring or late fall when bark
  separates easily
• Must be cared for the same as a graft
• Should cover with tape or wax to prevent drying
  out

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ASEXUAL PROPAGATION

• T-Budding
• A bud is placed underneath the bark of the
  rootstock
• Named because of the cut made in the rootstock
• Bud is secured and covered with rubber bands or
  tape

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ASEXUAL PROPAGATION

• Patch Budding
• Scion is a bud cut with a small section of bark
• Similar piece of bark is cut from rootstock
• Used when bark is thicker such as on nut trees

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ASEXUAL PROPAGATION

• Layering is a simple method where roots are
  formed on a stem while the plant is still
  attached
• Easy to do because no cutting is required and
  plant can transpire normally
• Larger new plants can be produced but limited
  amounts can be made
• Four basic types Simple, Trench, Mound and Air

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ASEXUAL PROPAGATION

• Simple and Trench layering are very similar
• While still attached to main plant, a piece of
  the stem is buried in a trench or hole 3-6 inches
  deep
• Buried section produces roots and can then be
  removed from the plant as a duplicate
• Mound layering is done in early spring on
  vegetative perennials or suckers of trees
• New growth or shoots are cut back to 2-4 inches
  tall
• Soil is mounded to bury shoots which will then
  form new roots and new shoots and separated

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ASEXUAL PROPAGATION

• Air Layering
• A portion of the bark is removed
• Moist medium like peat moss is applied to the
  bare stem and wrapped with plastic
• Roots form and the branch can be removed

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ASEXUAL PROPAGATION

• Separation and Division multiplies plant numbers
  naturally
• Separation is when natural structures of the
  plant are separated to grow on their own
• Many bulbs and corms are separated
• Division requires cutting of the plant material
  into separate sections
• Rhizomes, Tubers and Crowns are divided becoming
  separate plants
• Grasses, potatoes and perennial plants are divided

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ASEXUAL PROPAGATION

• Tissue Culture or Micropropagation is the most
  demanding of the asexual propagation methods
• Small pieces or masses of cells are taken from a
  growing plant and placed in agar
• Agar is a nutrient rich, Jell-O-like growing
  medium
• A few cells contain enough DNA to grow into a new
  plant identical to the donor plant
• Requires sterile conditions such as a laboratory
• Most strawberries are produced this way

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The End!!!