1. Introduction to Horticulture
PLANT PROPAGATION
Introduction to Horticulture

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

3. 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.

4. 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

5. 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

6. 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 don’t store

7. 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

8. SEXUAL PROPAGATION Typical Certified Seed Label
Origin
Germination %
Purity %
Other Ingredients
Must be present for sale and shipment of seed

9. SEXUAL PROPAGATION
Parts of a Seed

10. SEED GERMINATION Germinate means to grow or sprout
Germination is dependent upon:
Moisture
Temperature
Air
Light
Medium

11. SEED GERMINATION Moisture Temperature Air
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

12. SEED GERMINATION Light Medium
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

13. 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

14. 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

15. 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

16. SEED GERMINATION Site Selection Seedbed Preparation Planting Date
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)

17. SEED GERMINATION Planting Depth and Spacing Moisture
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

18. 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

19. 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.

20. 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

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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. ASEXUAL PROPAGATION Bark Grafts
Similar to a cleft graft where rootstock is larger
Done in early spring when bark separates easily

29. 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

30. 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. 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

37. The End!!!