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Chap 12. Plant Propagation I. Three Methods of Plant Propagation a.Sexual Propagation (Seed Propagation) b.Asexual Propagation (Vegetative Propagation)

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Presentation on theme: "Chap 12. Plant Propagation I. Three Methods of Plant Propagation a.Sexual Propagation (Seed Propagation) b.Asexual Propagation (Vegetative Propagation)"— Presentation transcript:

1 Chap 12. Plant Propagation I. Three Methods of Plant Propagation a.Sexual Propagation (Seed Propagation) b.Asexual Propagation (Vegetative Propagation) c.Micropropagation (Tissue Culture)

2 II. Sexual Propagation 1. Seed production Mostly in Western States - California, Oregon, Washington, Idaho - Low humidity (less fungal, bacterial diseases) - Mild temperature (good for flowering, seed set) - Even distribution of rainfall throughout year - Isolated from major production areas Hybrid Seed Production - Use of male sterility (US production) - Hand pollination (Developing countries) Labor Intensive Operation - Pollination - Harvesting, cleaning, and handling

3 2. Seed Storage Optimum condition for seed storage –Low temperature (0-32 o F) –Low humidity (less than 10% RH) Practical storage conditions –32-50 o F, 50-65% RH Seed longevity varies by species –Most annual flowers last 1-2 years –Woody plants 5-20 years –Lotus seed known to last over 1000 years –Permanent storage at cryogenic temperature(-196 o C)

4 3. Seed Germination Seed Germination Test –Seed viability –Determined by percent germination (100 seed lots) –Tetrazolium (TTC) test to find tissue viability Enhancement of % Germination –Seed quality and storage conditions –Seed priming to enhance germination vigor and uniformity

5 Seed Priming  A process of prehydrating and redrying seeds to enhance their subsequent germination performance  Used for flower and vegetable seeds for uniform and vigorous germination Us e of osmotic solution

6 Breaking Seed Dormancy Scarification –Overcomes physical seed dormancy (Seed coat is impermeable to water) –Three methods Mechanical abrasion Hot water ( o F) Acid treatment (concentrated sulfuric acid) (Seed coat is impermeable to water) Stratification –Overcomes physiological seed dormancy (Embryo dormancy, internal dormancy) –Moistened, cold storage Storage at 32 o F for 1-9 months) –Some species may require warm stratification Viburnum, Redbud

7 Two Different Types of Germination Epigeous Germination –Cotyledons are exposed above ground –Epicotyl and hypocotyls are also visible –Cherry, soybean, radish Hypogeous Germination –Cotyledons are buried in the ground –Only epicotyl are visible –Peach, pea, apricot

8 Germination of Angiosperm Seeds

9 Embryo Culture  Immature zygotic embryos are excised and cultured in vitro to obtain viable seeds  Used in abortive inter-specific crosses (i.e., potato)  Used for embryos lacking endosperm (i.e., orchids) Double fertilization In-ovulo Embryo culture Seed germination

10 4. Field Establishment Direct Seeding –Use of pelletized seeds –Mechanical planting Transplanting –Mechanical transplanting Use of fluid drilling Plug-grown seedlings –High value vegetable crops Lettuce, cabbage, celery (i.e., California, Arizona)

11 Seedling Production in Greenhouse

12 II. Vegetative Propagation Use of Apomictic Seeds Use of Specialized Vegetative Structures Adventitious Root Induction (Cuttings) Layering Grafting

13 a. Use of Apomictic Seeds Apomixis = Development of seeds from maternal tissue inside ovule Some apomictic seeds are formed from megaspore mother cells Apomictic seeds produce plants that are genetically identical as maternal plants Examples: Mango, Kentucky bluegrass, Citrus

14 How is Apomictic Seed Formed?  Asexual seed formation from maternal tissues around zygotic embryo inside an ovule  Apomictic seeds can be formed from nucellar tissues, egg mother cell, flower heads (bulbils)  Found in Kentucky bluegrass, dandelion, citrus, Alliums Nucellar embryos in Citrus

15 b. Specialized Vegetative Structures Runners (Stolons) Bulbs Corms Rhizomes Off-Shoots Stem Tubers Tuberous Roots Root Suckers

16 Runners (Stolons) Above-ground running stems New plants are formed on each node Examples: Strawberry, Spider Plant, Buffalograss StrawberryBuffalograss

17 Bulbs  A specialized underground organ consisting of a basal plate, growing points, flower primordia, and fleshy scales  Found in monocots  Tunicate bulbs - Onion, tulip, garlic, hyacinth  Non-tunicate bulbs – Easter lily, Oriental lily  Bulblets, bulbils, stem bulblets

18 Scaly Bulbs: Easter Lily

19 Corms: Gladiolus

20 Rhizomes  Laterally grown underground stems  Iris, ginger, lily of the valley, orchid

21 Offshoots  Lateral shoots, often with roots at the base, produced on main stems which can be separated and grown as independent plants  Examples: Pineapple (slip), dendrobium, cymbidium

22 Stem Tuber  Tuber is a swollen, modified stem structure that functions as an underground storage organ  Examples: potato, caladium, Jerusalem artichoke Use of eyes in potato propagation

23 Tuberous Roots

24 b. Cutting Propagation Detached stems and roots are used to induce adventitious roots or shoots Woody Plants Hardwood cuttings Softwood cuttings Semi-hardwood cuttings Single-node cuttings Root Cuttings Problem with phenotype conversion in chimeric plants

25 Influence of IBA on Rooting-Cordia parvifolia 1-Control, 2-50% ethanol, ppm, ppm, ppm, ppm, ppm, ppm, ppm IBA

26 Cutting Propagation in Jojoba Regular Stem Cuttings –Use 4-5 nodes –Semi-hardwood cuttings Single Node Cuttings –Double-eye single node cuttings –Single-eye single node cuttings

27 Single Node Cuttings of Jojoba 5-node Single Node Cuttings DE SE DE SE

28 Softwood Cuttings-Peach

29 Hardwood and Semi-hardwood Cuttings Stock plant nursery, 2-making cuttings, 3-bundles of cuttings, 4-IBA treatment, 5-rooting in artificial mix, 6-outdoor misting system for rooting

30 Pauk Ecke’s Poinsettia Greenhouse

31 Herbaceous Cuttings - Carnation

32 Leaf Cuttings-African Violet, Piggyback Plant

33 Chimeras  A plant that is composed of tissues of more than one genotype  Chimera (Greek Word) A mythological monster, having a lion’s head, a goat’s body and a serpent’s tail Chimera Periclinal Chimera

34 Three Types of Chimeras

35 Examples of Chimeric Plants ChrysanthemumRose

36 Propagation by Grafting Requirements for Success –Compatibility between stock and scion –Alignment of cambium layers –Prompt handling Grafting Methods –Cleft grafts –Whip-and-Tongue –Side grafts –Budding –Inarching –Bridge Grafts –Topworking

37 Use of Herbaceous Grafting 1.Virus Indexing 2.Synthetic Plants 3.Construction of Genetic Chimeras 4.Improved Crop Performance 5.Research in Plant Physiology 6.Enhancement of Esthetic Value

38 Various grafting methods in vegetables with or without rootstock root systems Cucurbits (watermelons, melons, cucumbers, squashes, etc.) Solanaceous crops (tomatoes, peppers, eggplants, paprika, etc.)

39 Eggplant/potato Tomato/eggplant Cabbage/Radish Chinese cabbage/Radish

40 Robotic Grafting Machine

41 ※ After placing the scion on the top of rootstock to match the vascular bundle, thread or clips are used to hold the position. Cut Diameter of scion: 10 mm. Vascular bundle Hylocereus trigonus, the most popular rootstock for cactus grafting * Standard rootstock length : 9 cm long * Diameter of rootstock: 30~ 35 mm

42 G F H


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