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DESCRIPTIONAsexual Propagation. Asexual Propagation?. A= without Therefore asexual= without sex Without sex = No pollination. How?. Clones the parent plant to create identical replicas of the plant. Uses plant parts such as leaves, roots, and stems to start new plants. - PowerPoint PPT Presentation
Asexual Propagation?A= withoutTherefore asexual= without sexWithout sex = No pollination
How?Clones the parent plant to create identical replicas of the plant. Uses plant parts such as leaves, roots, and stems to start new plants.
Reasons to Use Asexual PropagationTo produce uniform, superior plantsMany plants dont come true from seedsSome plants dont produce viable seedsTake advantage of useful freaks of natureThere are several reasons why one would choose to propagate plants asexually:1. Once a plant has been found to posses superior traits, these superior traits can be expressed over and over again through asexual propagation. Plants propagated in this manner are genetically identical their parent plant. Plants of uniform quality are produced.2. Some plants dont come true from seeds. This simply means that because of genetics or other reasons, plants may not produce seeds that will result in the same plant. Most hybrid plants do not produce seeds that will stay true in producing new plants with the same characteristics as the parent.3. Some plants dont produce viable seedsthese seeds for whatever reason will not germinate.4. One of the most important reasons is to take advantage of freaks of nature or Genetic Mutations.MutantTissueThis slide illustrates a plant that has a genetic mutation. Although one may try to reproduce a plant with blue limbs from seed, it will not happen if the blue limb is caused by a genetic mutation. These mutations can only be reproduced by asexual means. This is how cultivars are started and produced. If you remember, a cultivar is a cultivated variety. A cultivar is a group of plants within a species that has a particular characteristic an can refer to plants propagated sexually or asexually. Man must propagate a cultivar in order to continue the line. We now may reproduce this mutant tissue. A group of plants derived from a single individual plant.Disadvantage:NO Genetic Diversity!What is a CLONE?Cloning has been such a controversial topic lately in the animal world. However, we in horticulture clone all the time. If a plant has been propagated asexually, it has been cloned.
The disadvantage of cloning is NO Genetic Diversity. This can be a disadvantage because if a disease occurs for which the plant has no immunity, all plants in this cultivar can be wiped out because they are all genetically identical.Most common type of asexual propagationCommon Types of Cuttings:Stem CuttingsLeaf CuttingsLeaf Bud CuttingsRoot CuttingsCuttings
Cuttings are covered in this presentation because they are the most common and simplest form of asexual propagation.There are several common types of cuttings. Stem cuttings, leaf cuttings, and leaf bud cuttings.
When taking stem cuttings, one would ideally choose a section of stem with several nodes. These nodes are places for roots and new shoots to develop.Leaf cuttings are done quite often with varieties of begonia. For example the large leaf of a Rex Begonias is cut and pinned down to the surface of the growing media. The veins are then cut in various places. Under the right conditions, new plants will form at each of these cuts.
Leaf bud cuttings are used extensively in producing plats such as the hydrangea. Rules for CuttingsTypically take cuttings from new growthCollect cuttings early in the morningCollect cuttings from healthy stock plantsProvide proper environment for rooting
There are various rules for cuttings. Cuttings should be taken from new growth if possible. In new growth, cells are actively dividing. This helps to contribute to the formation of adventitious roots.Cuttings should also ideally be taken in the morning. The morning is the time of day when plants are most full of moisture. When taking a cutting, you are taking away the plants roots and hence its access to water. The cutting does however transpire. Therefore one would want to take cuttings when the plant is full of moisture. Then the plant must be placed in the proper environment for rooting.Herbaceous CuttingsSucculent greenhouse plants can make numerous cuttings from parent plantcuttings 2-6 inches long
Herbaceous CuttingsStem Cuttingsremove bottom leavesroots will grow from the node where leaves were attachedUse rooting hormone- ROOTONEspeeds rooting process
Rooting HormonesIndoleacetic Acid (IAA)natural plant hormonecauses roots to form on stemsIBA & NAAMost commonly usedComes in powder or solution
Rooting hormones are used to hasten rooting. These hormones stimulate cell division and differentiation. They are useful in getting plants to root that are particularly difficult. Many woody species require rooting hormone for successful rooting of cuttings.
When using the hormone, the end of the cutting stem should be scraped or wounded. This helps to stimulate cell division and differentiation. The plant is then dipped in the rooting hormone, which may come in a powder form or a solution.The Proper Environment...The MediaMust be sterileMust provide air exchangeMust hold moistureBottom heat helps speed rootingThe AtmosphereNeed HIGH relative humidity near 100%
The proper media for cuttings is much like the proper media for any plant. The media should be sterile (free of weed seeds and/or disease). It must allow air to pass through. It must hold moisture.
The atmosphere must be high in relative humidity. The higher the relative humidity, the less likely the cutting is to lose water.Herbaceous CuttingsLeaf Cuttings
African VioletUse leaf and petioleRex BegoniaVivaparious leaf cutting Leaf Section cuttingSnake plant
Herbaceous CuttingsLeaf-bud cuttings
cut bud and leaf from stemcut leaf to a smaller sizerequires less moisturefirm into soil, water and cover in a moisture right container.Can make many more cuttings from parent plant than with stem cuttingsrooting hormone should be weaker strength.
Herbaceous CuttingsRoot Cuttings
Can be made from any plant that will sprout or sucker from the root.Cut roots 1/8 to 1/2 inch in diameter in pieces 1-4 inches long.place in sand in a flatwatercover with glass or plasticwhen new shoots sprout move plants to nursery rowex: raspberry
Woody & Semi Woody CuttingsWhen to take cuttings:After current or present seasons growth has partially hardened.Cuttings should still be able to bend.Woody & Semi Woody CuttingsStem CuttingsCollecting cuttings:Early morning is the best time to take cuttings.
Woody & Semi Woody Cuttings Making CuttingsMake cutting 2-4 inches long. Inch below a leaf, bud, or side shoot.Remove any blooms on cutting.
Woody & Semi Woody Cuttings Caring For CuttingsPlace cutting in a sanitizing water/bleach solution immediately after taking cutting.Be sure to remember which is the top of the cutting.If you bury the top of the cutting, the cutting wont root.Woody & Semi Woody Cuttings Caring For CuttingsCut bottom at a 45 angle.allows more surface area to contact media for water absorption.
Woody & Semi Woody Cuttings Preparing ContainerFill plug tray with sterilized medium. Use a dipple to dipple holes in the media for easy insertion of cutting.
Woody & Semi Woody Cuttings Treating CuttingsStrip cuttings lower leaves.will prevent the cutting from rooting.Dip cutting in rooting hormone #3.chemicals which help cuttings grow more quickly and grow a larger number of roots.
Woody & Semi Woody Cuttings Inserting CuttingsPlace dipped cutting indibbled hole.Gently press media around cutting.Label cutting with name and variety, include name of rooting hormone used.
Woody & Semi Woody Cuttings Care of Cuttings With GreenhousePlace finished plug tray in greenhouse.Water cuttings with an automatic mist system. Bottom heat tubing stimulates root growth.
Woody & Semi Woody Cuttings Care of Cuttings Without GreenhouseEnclose plug tray in clear plastic.Place out of direct sunlight.
Woody & Semi Woody Cuttings Rooting Of CuttingsCheck for roots by pulling out cutting.Immature root system= roots dont hold soil, so soil crumbles in hand.Root bound= roots coiled tightly around soil.Woody & Semi Woody Cuttings Rooting Of Cuttings*Mature root system= roots hold soil, so soil doesnt crumble in hand.*Ideal and ready to transplant.
Growth on the tips or sides is normal, but does not indicate root growth.