Propagation by Seed

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Propagation by Seed

• Seed Selection and Hybridization
• (Chapter 4)

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Uses of Seeds in Propagation

• Large scale agricultural crops
• Vegetable, garden and florist crops
• bedding plant industry
• Rootstocks for grafting fruit trees
• Ornamental shrub and tree seedlings
• Reforestation for natural areas

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Seed Selection in Herbaceous Sp.

• Breeding systems
• Self Pollination
• Cross-Pollination
• Apomixis- Seed production is asexual. Embryo
  formation bypasses meiosis and fertilization.
  Resultant plant will be same as seed parent.

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Control of Genetic Variability

• Isolation
• Roguing
• Seedling Progeny Tests

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Catregories of Seed-Propagated Cultivars

• Landraces
• Heirloom Varieties
• Seed Savers Exchange
• Lines

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Seed Production of True to Type Herbaceous
Cultivars

• Commercial Seed Crop
• Pedigreed Stock System
• Breeders Seed
• Foundation Block-gtIncrease Block-gtCertified Seed
• Hybrid Seed Production

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Seed Selection and Production Systems

• Seed Collection Zones
• Seed Production Areas
• Seed Orchards

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Legal Controls to Genetic Purity

• Seed Certification
• Breeders Seed
• Foundation Seed
• Registered Seed
• Certified Seed
• Tree Certification Classes
• Plant Variety Protection

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Seed Development

• Chapter 5

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What is a seed?

• Mature Ovule
• embryo
• protective covering-Seed Coat
• storage tissue-Endosperm

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Fruit, Seed and Embryo Formation

• Pollination
• Double Fertilization

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Miscellaneous Terms

• Parthenocarpy-fruit development without seed
  formation.
• Vivipary- seed germinations without maturation
  drying.
• Recalcitrant Seeds-germination must proceed soon
  after maturity, or, must be stored at high
  humidity. Examples Coffee, coconut, oak

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Seed Testing

• Viability Determination
• Standard Germination Test
• Excised-Embryo Test
• Tetrazolium Test
• X-Ray Analysis
• Purity Determination
• Vigor Testing

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Pre-Sowing Treatments

• Seed Protectants
• Chemical Treatments
• Biocontrol
• Heat Treatment
• Seed Coating
• Germination Enhancement
• osmotic seed priming
• matrix seed priming
• pre-germination, fluid drilling

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Seed Germination

• Conditions
• Viable
• Environment
• Overcome any primary dormancy condition

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Phases of Seed Germination

• Phase I - Water imbibition
• Phase II Lag
• Mitochondria maturation
• Protein synthesis
• Metabolism of storage reserve
• Enzyme activation
• Phase III Radicle Emergence

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Seedling Emergence

• Embryo Growth
• Seed leaves (cotyledons)
• Radicle
• Plumule
• Hypocotyl
• Epicotyl

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Seedling Germination in Dicots

• Epigeous
• Hypogeous

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Seed Dormancy

• Primary
• Physical
• Mechanical
• Chemical
• Secondary-after water imbibed, unfavorable
  conditions exist
• Temperature
• light

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Overcoming Dormancy

• Scarification
• Mechanical
• chemical
• Stratification
• Moist chilling
• Warm moist
• Excised embryo techniques

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Seed Storage

• Recalcitrant
• Orthodox
• medium lived
• long lived
• Storage and Seed Germination
• moisture, temperature
• Types of Seed Storage
• Open Storage, Sealed containers, conditioned
  storage, moist-cool storage,

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Seed Planting

• Outdoor
• Indoor/Greenhouse Conditions

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Seed Characteristics

• True to name
• Viable
• Clean stock
• Disease and insect free
• Graded to size

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Outdoor Seeding

• Vegetable and/or Flower Varieties
• Direct Seeding
• Rows- drills
• Broadcasting topdressing cover

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Indoor/Greenhouse Seeding

• Containers
• Flats
• Plug trays
• Liner pots
• Soil Media
• Components
• Peat moss, perlite, sand, coir, etc.
• Percentages by volume

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Soil Treatments

• Pasteurization
• Sterilization
• Post planting treatments
• Fungicides
• Insecticides
• Rodenticides
• Herbicides

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Pasteurization

• Heating soil to temperatures at 140º-160º F for
  45 minutes. Use of steam is preferred.
• Kills harmful organisms, keeps beneficial ones.
• Cleanest method of treatment.

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Sterilization

• Use of heat to kill all organisms.
• Heat soil to 212º F
• No guarantee of the beneficial population of
  organisms to become established before the
  harmful ones.

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Seeding Methods

• Broadcast
• Rows
• Mechanical Seeder Plug trays
• Vacuum
• Drum

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Seeding Methods

• Planting depth- varies with species
• Post planting care
• Water, fungicide, rodenticides, etc.
• Environmental conditions
• Sanitation
• Bottom heat

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Seeding Problems

• Over-watering or underwatering
• Diseases
• Insects
• Rodents

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Diseases

• Pythium sp.- water molds
• Phytophthora sp.
• Rhizoctonia sp.
• All of the above species cause a condition known
  as

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Damping -Off

• A condition in which the fungal organism invades
  the crown tissue (at the base of the seedling)
  and causes it to collapse, resulting in death of
  the plant.
• Condition occurs in over-watered situations,
  where there is free standing water.

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Seedling Growth

• Post germination care
• Transplanting
• When first set of true leaves are developed.
• Cell packs-six, jumbo, 24s, 48s, etc.
• Liner pots
• Field
• Soil mixes?