Plant Propagation(Sexual & Asexual)

Prepared by: L. Robert Barber, Roland Quitugua & Ilene Iriarte

For: Guam Cooperative Extension Service & Guam

Department of AgricultureFunding 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:– 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