Download Plant Propagation - MrsLongHorticulture

Plant Propagation
• One of the most rewarding and satisfying
activities in horticulture is plant
propagation.
• Plant propagation is the heart of all work in
the field.
What is plant propagation?
• Making new plants from old plants
• There are two (2) types of propagation:
sexual
asexual (vegetative)
Why propagate plants
• To multiply numbers
• To save wanted traits
• To improve a species of plants
• Biotechnology helps improve food
production, quality of flowers, and
resistance to disease in plants.
• Gene manipulation may someday cure
many of our most deadly diseases.
Sexual Propagation
• Involves the union of pollen with an egg in
the ovary.
• These male and female cells may be from
the same plant (self-pollination) or from
• Separate parent plants (cross-pollination)
• Seeds are a way of rapidly increasing the
number of a certain plant.
• Many plants reproduced from seed will
differ from the original plants.
• This is because genes from each of the
parent plants are represented in the new
plant. Thus, a variety is created.
Principles of Genetics
• Gregor Mendel, an Austrian Monk, is
recognized for discovering the basic
principles of genetics.
• Genetics is the study of how characteristics
are passed from parents to offspring.
• He used observations of pea plants to
develop these principles:
• In all organisms, there is a pair of genes in
every cell that determines every trait in
that individual organism.
• Individuals receive one gene for each trait
from each parent.
• Genes are transmitted from parent to
offspring as unchanging units.
• In the making of reproductive cells, gene
pairs separate; with only one gene for
each trait is contained in each gamete.
(sex cells: pollen or eggs)
Each gene passed on by the parent plant is
called an allele
• A visible characteristic is called a
phenotype
• The combination genes from parent plants
is the genotype
• When different genes are present for a
single trait, in most cases only one trait will
be expressed (seen) in the offspring.
• The seen trait is called a dominant trait
The masked or unseen trait is a recessive
trait
• A dominant allele is written as an upper
case letter symbol (T)
• A recessive allele is written as a lowercase
letter symbol (t)
• In plants, the color red is a dominant trait,
white flowers are a recessive trait.
• If a plant has two (2) dominant genes for a
trait, it is called pure dominant. (TT)
• Dominant homozygous
• A plant with two(2) recessive genes is pure
recessive (tt)
• recessive homozygous
• A plant with two (2) different genes for a
trait (Tt)
• It is heterozygous.
• Even though the individual has the
recessive gene, the recessive trait is not
seen. Only the dominant feature shows up
Expected & Observed Results
• Question:
How can knowing the types of genes that
each parent has be helpful?
• Traits the offspring will have can be
predicted
• The color, size and shape of the petals
can be pre-determined by understanding
what traits will appear when two plants are
cross-pollinated.
• Biotechnology allows us to build or re-build
plants to produce better quality flowers,
fruit or growth habit by combining the best
traits of different plants.
Hybrid Seed
• Hybrid seed are specially produced seed
that germinate into plants which appear to
be genetically identical.
• If seed are taken from these hybrid plants,
the resulting plants will have a variety of
combinations of traits. If only the original
traits are desired, do not use seed from
hybrid plants.
• Chose seed from named varieties only.
Sowing Seed
• Seed propagation of is used for many
herbaceous annuals, and perennials.
• The proper environmental and cultural
conditions must be provided:
1) temperature
2) moisture
3) light
4) media
1)Place media in container (water gently)
2)Slowly shake seed onto media
a. broadcast: randomly & evenly shake out
over the media
b. row plant: place seed in even rows*
(*best method to avoid spread of fungus /diseases)
3) cover seed with a thin layer of media
4) water gently
5) place in area with higher humidity, and
increase soil temperature to specified level
for the seed growing. (bottom heat range
65’ – 70’)
6) label container with Named variety. date
sown
Asexual Propagation
• Reproduction without sex.
• Occurs naturally with most plants,
• Has become very important in the
Horticultural Industry.
• Clones – plants genetically identical being
produced asexually (uses part of a plant)
• Pluses to clones:
The new plant is genetically identical
The new plant is quicker to get to mature
size.
Disadvantages of Using Seed to
Propagate New Plants
• Seedlings may take too long to mature
• Seed from some plants may be slow to
germinate (Adds to Costs)
• Varying genetics transfer to off spring with
each generation.
• Seed production is mainly used when
growing bedding plants,
(annuals,perennials, and vegetables)
• Asexual Propagation Provides:
• 1. uniformity of large numbers of plants
• 2. to sustain wanted or desired traits
(characteristics)
• 3. rejuvenate sick or scraggly plants
Methods of Propagating Plants
Asexually
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Stem Cuttings
Cane Cuttings
Leaf Cuttings
Leaf-bud Cuttings
Layering
Air Layering
Division and Separation
Tissue Culture
Grafting
Grafting
• The method of grafting is connecting two
plants or plant parts together so they unite
and continue to grow as one plant.
• Grafting is possible only when the two
plants are related at least at the family
level.
• A graft consists of two parts:
• Scion:
• A short piece of stem with 2 or more buds,
becomes the top of the new plant
• Understock: (rootstock)
• The lower part of the graft. Becomes the
root system of the new plant
•
Reason(s) for grafting
• Propagate plants difficult to propagate by
other means
• Used most often in orchards, shade trees,
and roses
• Creates dwarf plants
• Creates plants with more hardy
characteristics
Types of Grafts
• Whip and tongue graft• Used of wood smaller than an inch
• Allows vascular tissue to match up
Types of Grafts
• Cleft graft• Used when the understock is larger than
the scion.
• Vascular tissue must match up so scions
are inserted at the edges of the understock
Types of Grafting
• Slip Graft (Side Graft)• Quickest graft, although hard to keep
together (lined up)
Types of Grafts
• Saddle graft – scion is cut so it sits over the
understock a very tight fit is achieved
Budding/Bud Grafting
• Similar to Grafting except the scion is a
single bud with a small section of bark.
• Practiced in early spring just before plants
break dormancy.
Types of Budding
• T- Budding • buds removed from a plant with desirable
traits then attached to an understock to
form new plant
• The rootstock is cut in a “T” shape, the bud
is slipped into the cut and tied off with a
band. It is then covered with beeswax
Types of Budding
• Patch Budding- desired bud is cut out like a
stamp patch. The same shape patch is cut
out of the understock.
• The bud is placed into the patch on the
understock then tied off and covered with
beeswax
• For both types of budding, the top of the
rootstock is cut just above the new bud
once it opens to become the new plant's
top
• Grafting is important to the horticulture
industry because it has enabled growers to
create new plants while using the best traits
of others.
• The wine industry of Europe was saved by
the inferior rootstock of the 'Concord'
Grape.