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National Tree Seed Laboratory

National Tree Seed Laboratory United States Distribution of Juniperus J. monosperma J. pinchotii J. silicicola J. scopulorum J. virginiana United States Distribution of Juniperus Western Junipers J. osteosperma J. ashei J. deppeana J. communis

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National Tree Seed Laboratory

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  1. National Tree Seed Laboratory

  2. United States Distribution of Juniperus J. monosperma J. pinchotii J. silicicola J. scopulorum J. virginiana

  3. United States Distribution of Juniperus Western Junipers J. osteosperma J. ashei J. deppeana J. communis

  4. USDA Forest ServiceNational Tree Seed LaboratorySeed Testing Data 2002-1962

  5. Juniperus Seed Collection Problems • Native seed collections contain many empty seed • Unpredictable and variable seed crops due to harsh weather conditions • Seed maturation periods vary by species- immature and mature seed easily mixed together during collection • Western species in remote areas-inaccessible for easy collection • Equipment for removal of empty and low vigor seed not affordable by all processors

  6. J. scopulorumSeed Cleaningat Big Sioux Nursery, South Dakota • 10-15% first year green berries in field collection • Green berries will not float out • Fanning mill to remove green berries • 5% green berries left after cleaning • 10% empty seed • 60-70% germination in nursery bed • Plant seed in July • Plant seed near irrigation lines to keep seed moist before winter • Do not let seed dry out

  7. J. scopulorum seed cleaning USDA Bridger Plant Materials Center, Montana • Mascerate berries- line with abrasive material for better pulp removal • Use lye or citrus soap for softening pulp (1.3 ml/liter of lye); 4.9ml of citrus soap to 1.4 kg berries • 1.8 to 4.1kg berries = .45kg clean seed • Household blender with taped blades for small lots • Empties float in water • Germination ½ of viability percent • Best germination with 45 minutes H2SO4 soak + 116 day warm + 150 day cold, moist stratification • Check for filled seed on tree before collection

  8. JuniperusSeed Germination Problems • Complex dormancies- embryo, endosperm, secondary dormancy • Long stratification periods- vary warm and cold cycles • Seed viability much greater than germination percentages • Germination unpredictable in laboratory and nursery • Seed sources may respond differently to stratification treatments due to introgression • Wildland seed viability – 22 to 35%

  9. Juniperus scopulorumColorado State Forest Nursery (bareroot seedlings) • Sow seed in nursery beds late July- soil temperature @ 21°C • Frost fabric on nursery beds- raised temperature 3°C • Use winter irrigation to prevent seed dessication • 2-0 bareroot, 2-1 container transplants • Tarpaper container used for transplants seedlings in shadehouse

  10. Seed treatment for container seedlings of J. scopulorumColorado State Forest Nursery • Bury J. scopulorum seed in nursery bed in summer, extract in February • 70% cracked seed coats, radical emerging • Greenhouse sowing in February • Harden off in late July in shadehouse • Still growing in September & October

  11. Juniperus scopulorum Seed StudyUSDA National Tree Seed Laboratory • Weight affects mean viability, number of dead, percent empty seeds • Gravity table increases viability by redistributing seed in seedlot • Heavy seed has the best viabiltiy

  12. J. scopulorum germination studyNational Tree Seed Laboratory

  13. Juniperus virginianaEastern redcedar Seed Treatments • 24 hour water soak, 30 day warm moist, 90 day cold moist used in Nebraska • 96 hours citric acid soak (10,000 ppm), 6 weeks warm moist (24°C), 10 weeks cold moist (5°C) • Best germination temperature 15°C • Secondary dormancy induced above 15°C • Seeds heavier than water had 75-80% germination container seedlings

  14. J. virginiana seed treatments seed testing data 2002-1962

  15. Juniperus communisSeed Treatments • 15 minutes in H2SO4 • Rinse & use baking soda to neutralize acid & rinse again • Soak in water overnight • Plant in July, germinate in April-May • 25% TZ yields 20% germination • 50% TZ yields 30-35% germination • Seed source – ITALIA • Lawyer Nursery, Montana

  16. Juniperus osteospermaSeed treatments • 45 days moist warm, 120 days cold moist stratification • Germination inhibited above 15°C • Seed stored at 10-12% moisture viable for 9 years at –7 to 5°C • 12 week aerated water soak at 5°C yielded 50% germination • Add GA3 to aerated water, germination is 64%

  17. Juniperus monospermaSeed Treatments • Some seedlots can germinate without stratification • 48 hour running water, 30 minutes soak in 30% hydrogen peroxide, germination was 79% over 47% for untreated seed • 48 hours leaching + 90 day cold, moist stratification had 88% germination • 24 hour hydrogen peroxide soak (5%) + 24 hour GA3 soak (250ppm) before 30 day cold stratification had greatest germination rate

  18. Critical Elements • Germination temperature – secondary dormancy induced above 15°C • Seed dehydration in nursery induces secondary dormancy – winter irrigation • Warm and cold, moist stratification still best for breaking dormancy for nursery • Imbibe seed before stratification • Germination about 50% of viability • Heavy seed has best viability • Train collectors not to pick immature seed

  19. Conclusion An international network of resource specialists working with Juniper forests is needed to create a comprehensive program of research and technology transfer to generate and implement new knowledge. (Ciesla 2002; Forests, Trees,and Livelihoods vol 12)

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