Seed Propagation

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Seed Propagation
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Seed preparation

• Seed treatments (if desired)
• Fungicide
• 5.25 Na hypochlorite (CloroxH2O at 19) for
  10-15 min.
• 11 solution of hydrogen peroxide (3) water
  for 10 min.
• Hot water - 120o-135o F for 15-30 minutes
• Soaking
• Speeds up the germination process
• Most herbaceous species can benefit from 8 hours
  of soaking.
• Dont expose imbibed seed excessively to air
• Overcome dormancy requirements

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Dormancy

• Not same as quiescence - (environmental factors
  not right)
• Thermodormancy
• Moist chilling needed (32o-50o F)
• Impermeability to water
• Mechanical scarification may be needed
• Can place in hot water, remove heat, let stand
  for 12-24 hours
• Chemical inhibitors
• Water leaching needed

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Seed Quality

• Germination test
• Germination percentage
• Germination rate

• Tetrazolium test
• Seeds soaked, then dissected longitudinally
• One half put in 0.1 tetrazolium chloride
  solution
• Living tissue stains red dead tissue does not
  change

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TZ test
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Seed Quality

• Seed purity
• other materials (inert)
• seeds of other varieties
• weed seed
• pure live seed
• PLS ( germination X purity)/100

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Seed longevity

• Depends on
• Genetic makeup
• Temperature
• Relative humidity
• Dried to 7 moisture, under low humidity and
  0-4º C - can be stored for a long time

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Temperature requirements

• The most important environmental factor
  regulating germination
• Affects germination and rate
• generally the same over middle of temperature
  range
• Optimum for most plants is 77-86º F
• Fluctuating temperatures (day/night) are often
  better than constant ones
• e.g. 60-65º F for 16 hrs. 80-85º F for 8 hours

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Temperature requirements

• Cool-temperature tolerant plants
• Can germinate from about 40º F to lethal limit
• Broccoli, carrot, cabbage, etc.
• Cool-temperature requiring
• Fail to germinate at temperatures higher than
  77º F
• Celery, lettuce, onion, coleus, delphinium, etc.
• Warm temperature requiring
• Minimum of 50º F - chilling injury can occur
• Beans, eggplant, pepper, soybean, etc.

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Planting

• Seed depth (direct seeding)
• Large seeds 2 to 3 times the minimum diameter
  (depends of form of germination)
• Small seeds may be dusted on top and tamped down
• Seed tape
• Pelleted seeds
• Indoor seedling production

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