Transcript Organics - Guam Sustainable Agriculture Resource Page

Plant Propagation
(Sexual & Asexual)
Prepared by:
L. Robert Barber, Roland Quitugua & Ilene Iriarte
For:
Guam Cooperative Extension Service & Guam Department of
Agriculture
Funding provided by:
United States Department of Agriculture Natural Resources
Conservation Service, Western Region Sustainable Agriculture
Research and Education, Administration for Native Americans,, &
Sanctuary Incorporated
Sexual Propagation
• Involves the exchange of genetic material
between each parent: SEEDS
• Some advantages are:
– Cheapest & easiest method of producing large
number of plants (Soursop, Atis)
– Provides a strong tap root system
– Produce new varieties of cultivars
– Avoid certain diseases (resistant varieties)
– Can be the only way to propagate some species
Propagation by Seed
• Use seeds that are fresh & viable( will
sprout)
• Buy seeds that have been packaged for the
current year and your region
• Considerations:
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–
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Viability
Seed Orientation
Depth
Special practices (Scarification, Innoculation)
Collecting Seeds
• Hybrid seeds should not be saved:
– Will not be identical to parent plant
• Self-Pollinated or Non-Hybrid seeds can be saved:
– Similar to parent plant
• Saving seed saves money
• Harvest Seeds from healthy plants
– Some diseases can be carried by seeds
• Bringing in seeds or plants from other countries is how
many serious insects or diseases are introduced (Mango)
• Harvest seeds just before fruit is fully ripe
Storing Seeds
• Some seeds cannot be stored
– Parsley seeds need to be germinated right away after
they mature or they lose viability
• Once the seed has fully dried place them in an
air tight container
– Make sure to mark the name and date
– Store seeds at 40°F (Place in Refrigerator)
• Some seeds can be viable for up to 5 years or
longer if properly stored
• Other seeds are viable for only a few weeks
Seed Germination
• Factors that affect germination:
– Water (Moisture), Light, Oxygen, Temperature
– Water causes the endosperm (food supply) to swell, &
dissolves the nutrients in it
– Light can stimulate or inhibit seed germination
– Oxygen is needed so the embryo can break down
stored food & begin growing
– Seeds have optimum temperature range for sprouting
• Growing medium must be constantly moist, not
wet
Cucumbers propagated by seed
Seed Scarification
• Scarification is a process that breaks, scratches,
or softens the seed coat for moisture to enter
• Certain seed coats are very tough and need to be
scarified
• Two common methods of scarification are:
– Mechanical which break the seed coat with an object
– Hot Water dissolves waxy outer coat, involves placing
seeds in water 170 to 210 degrees F.
• It should soak for 12 – 24 hours
Asexual Propagation
• Does not involve the exchange of genetic
material
• Genetically identical to the parent
• Asexual propagation includes:
– Cuttings, layering, division, grafting,
budding, & tissue culture
Cuttings
• Cuttings consist of removing a portion of
the parent plant then the cuttings
regenerates into a new plant
• This is possible because the plant has the
ability to grows callus tissues that
differentiates into the missing plant parts
Cuttings
• Select new vigorous growth with no
flowers (remove buds), disease & insect
free
• Cut ¼ inch below a leaf node
– Pull off the leaves that are at the nodes which
are going below the surface
• Can use a rooting hormone (not in organic
operations)
Cuttings
• Insert cutting into moist rooting medium
• Rooting can take a few weeks to several
months
• Best results if cuttings are placed under a
mist system or in a moist chamber
Ti Leaf cuttings
Softwood or Hardwood Cuttings
• Some plants are best propagated by softwood
cuttings others by hardwood
• Softwood Cuttings:
– Use branches that haven’t become woody
– Make cuttings 2-10 inches long
– Make cuts just below leaf nodes
• Hardwood Cuttings:
– Cuttings are taken when tissue has become woody
– Make sure the plant is not fruiting
– Cut about 5-12 inches long
Root Cuttings
• Use newer root growth for cuttings
• Make cuttings 1-4 inches long at ¼ -½ inch in
diameter
– Cut a straight end closest to the stem (top side), and
the other end a diagonal cut (bottom side)
– So you know what side is up & what side is down
• Should be planted directly in rooting medium
• Collect root cuttings after the fruiting season is
over
Root cuttings of Lemai (Breadfruit)
Layering
• Is the process of developing roots on
shoots that are still attached to the parent
plant
• Good to use when only a few plants are
needed
• There are many different types of layering
– Simple, Tip, Compound, & Air Layering,
Layering
• Simple Layering:
– Bending the stem into the ground, burying it &
leaving the top 6-12 inches above ground, bend the
tip into a vertical position & stake it in place (tomato)
• Tip Layering:
– Dig a hole 3-4 inches deep, & bury the tip of the shoot
& cover it with soil
• Compound Layering:
– Similar to simple layering, but you can bury several
layers with one stem. Each section should have at
least one node (bud) buried and one node exposed
Air Layering
• Use stems that are pencil size or thicker. Choose
an area just below the node. Remove leaves &
twigs on the stem 3 – 4 inches above & below
this point
• For every inch of branch diameter remove 2X the
length of bark from the stem. Leave the inner
woody tissue exposed. Scrape the exposed stem
to remove the cambium tissue (Xylem/Phloem)
to prevent the tree from forming a callus (plant
response to damage).
Air Layering
• Surround the wound with a handful of
moist sphagnum moss (coconut husk),
wrap in plastic and tie with string, or
wrap it with electrical tape. Each end
needs to be secure to prevent moisture
loss
• After the stem is covered in roots, cut the
root ball below your airlayered stem
Citrus Air Layers
Division
• Is the process of dividing a number of
plants that are growing in clusters or
multiples
– Each piece needs to have a bud and roots
• Dig the plant carefully, loosen the roots &
lift the plant out of the ground
• Bananas and taro are common examples
Bulbs and Corms
• Bulbs (onion)and corms (banana, taro) can
be propagated by removing the suckers
that form at the base of the parent plant
• It can take up to 2 or 3 years for plants to
flower
Tubers & Rhizomes
• Tubers of tuberous plants can be dug up &
separated(potato)
• Each needs to have a segment of the
crown that contains at least one eye
• Rhizomes grow (underground) and
develop buds along their length
– Gingers have rhizomes
• It can be dug & cut into sections that each
contain at least one eye
Grafting
• Joins different segments of two different
plants, but same species
• Need to align the cambium layers of both
segments
• Some benefits of grafted plants:
– Identical to parent plant
– Vigorous, & early fruiting
– Two different varieties can be grown on same
plant