AGA142_PART 1_CHAPTER 4

• Planting material


  Seeds, seedlings, corms, or stem cuttings which used to propagate plants

  
• Plant propagation


  Process of growing new plants, new individuals from a plant having all the characters of the original one from a variety of sources: seeds, cuttings, and other plant parts

  
• Types of Plant Propagation

  • Sexual Propagation
  • Asexual Propagation/Vegetative

  
• Sexual propagation (seed)


  1. Flower production

  2. Pollination

  3. Embryo creation

  
• Seed


  A dormant plant which develops into a complete plant when subjected to environmental conditions

  
• Characteristics of good quality seeds

  • High genetic purity
  • High pure seed percentage (physical purity)
  • High germinability
  • High vigour
  • Higher field establishment
  • Free from pest and disease
  • Good shape, size, colour etc., according to the specification of variety
  • High longevity / shelf life

  
• Seed treatment


  Application of fungicide, insecticide, or a combination of both, to seeds so as to disinfect and disinfect them from seed-borne or soil-borne pathogenic organisms and storage insects
• Benefits of Seed Treatment

  • Prevents spread of plant diseases
  • Protects seed from seed rot and seedling blights
  • Improves germination
  • Provides protection from storage insects
  • Controls soil insects
• Types of Seed treatment

  • Seed dressing
  • Seed coating
  • Seed pelleting

  
• Conditions under which seed must be treated

  • Injured Seeds
  • Diseased seed
  • Undesirable soil conditions
  • Disease-free seed

  
• Seed germination


  The process where embryonic plant is contained in the seed leads to emergence of new plant

  
• Factors affecting Germination


  • Water
  • Oxygen
  • Temperature and Light
• Requirements for Seed Germination

  • Optimum temperature range
  • Light requirement
  • Moisture requirement
  • Medium/soil

  
• Methods to Break Seed Dormancy

  • Stratification – exposing the seed to cold
  • Scarification – abrading the seed coat
  • Soaking – use moderately warm, not boiling, water
  • Acid Soak – tough seed coats require mild acid solution to soften the seed coat
• Steps in seed germination

  1. Absorption of water

  2. Secretion of enzymes and hormones

  3. Hydrolysis of stored food into soluble form

  4. Translocation of soluble foods and hormones to the growing points
• Seed Sowing Depths


  Seeds should not be buried deeper than their diameter
• Seed Starting Equipment


  • Containers
  • Soil Blockers and Blocks
  • Soil Mixes
  • Lights
  • Heating Mats and Cables
  • Capillary Mats
  • Fertilizer
• Asexual propagation


  Also called vegetative propagation, is with the use of planting materials which are vegetative parts of any plant rather than seeds or spores which are reproductive parts

  
• Reasons for Asexual Propagation

  • Clone desirable specimens
  • Propagate difficult to germinate plants
  • Create larger plants
  • Save desirable plants from disease
  • Maintain genetic trait
• Techniques for vegetative propagation

  • Air or ground layering
  • Division
  • Grafting and bud grafting, widely used in fruit tree propagation
  • Micropropagation
  • Stolons or runners
  • Storage organs such as bulbs, corms, tubers and rhizomes
  • Striking or cu

  
• Vegetative propagation


  Use of planting materials which are vegetative parts of any plant rather than seeds or spores which are reproductive parts

  
• Vegetative propagation process


  1. Propagate is separated first from the parent plant

  2. Treated to induce regeneration

  3. Directly planted

  
• Plants derived from single parent thus there is no genetic change
• Plant propagated through asexual propagation has same characters as the parent

  
• Asexual propagation


  Reasons: Clone desirable specimens, Propagate difficult to germinate plants, Create larger plants, Save desirable plants from disease, Maintain genetic trait
• Advantages of asexual/vegetative propagation

  • Advantages
• Disadvantages of asexual/vegetative propagation

  • Disadvantages
• Techniques for vegetative propagation

  • Air or ground layering
  • Division
  • Grafting and bud grafting
  • Micropropagation
  • Stolons or runners
  • Storage organs
  • Striking or cuttings
  • Twin-scaling
  • Offsets
• Layering


  A means of plant propagation in which a portion of an aerial stem grows roots while still attached to the parent plant and then detaches as an independent plant

  
• Types of layering


  • Ground layering
  • Air layering/marcotting
• Ground layering


  1. Original plants set in ground with stem nearly horizontal

  2. Side buds grow upward

  3. Original stem buried up to some distance from tip

  4. Side branches root by end of growing season

  5. Some used for grafting rootstock

  
• Air layering


  1. Target region wounded or bark removed

  2. Rooting hormone applied

  3. Sufficient roots grown, stem removed and planted
• Division


  Herbaceous perennial plant broken up into two or more parts, with root and crown of each part kept intact
• Grafting


  Horticultural technique where tissue from one plant are inserted into those of another
• Types of grafting


  • Splice or whip grafting
  • Whip and tongue grafting
  • Approach grafting
• Grafting


  Two graft unions: Portion that develops into branches/foliage, Portion that develops into root system
• Bud grafting


  Tissues from one plant inserted into another so vascular tissues may join
• Splice or whip grafting


  Simple, popular, easy to perform method for small materials, done before bud break
• Whip and tongue grafting


  Similar to splice grafting but with added tongue for better fitting and rigidity, highest success rate
• Approach grafting


  Used to join plants that are otherwise difficult to join, can be done any time of year