National Tree Seed Laboratory United States Distribution of
National Tree Seed Laboratory
United States Distribution of Juniperus J. monosperma J. pinchotii J. silicicola J. scopulorum J. virginiana
United States Distribution of Juniperus J. osteosperma Western Junipers J. ashei J. deppeana J. communis
USDA Forest Service National Tree Seed Laboratory Seed Testing Data 2002 -1962 Total Germ Species Mean Germ Viabili ty Full Wet wt. Seed MC % % % Seeds/ Purity kg No. % % J. monosperma 3 2 39 76 98 . . . J. pinchotii 21 9 12 . 42 13. 2 100 30, 616 J. scopulorum 113 31 12 64 81 9. 2 99. 3 60, 074 J. silicicola 7 7 10 . 53 11. 9 99. 3 97, 784 J. virginiana 489 323 41 71 78 8. 4 95. 8 136, 651
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 areasinaccessible for easy collection Equipment for removal of empty and low vigor seed not affordable by all processors
J. scopulorum Seed Cleaning at 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
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. 9 ml of citrus soap to 1. 4 kg berries 1. 8 to 4. 1 kg berries =. 45 kg clean seed Household blender with taped blades for small lots Empties float in water Germination ½ of viability percent Best germination with 45 minutes H 2 SO 4 soak + 116 day warm + 150 day cold, moist stratification Check for filled seed on tree before collection
Juniperus Seed 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%
Juniperus scopulorum Colorado 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
Seed treatment for container seedlings of J. scopulorum Colorado 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
Juniperus scopulorum Seed Study USDA 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
J. scopulorum germination study National Tree Seed Laboratory Best Treatments Laboratory Oklahoma germination State Nursery germination 3 day water soak, 16 wks cold, 9 wks warm, 9 wks cold Germination in stratification 81. 75% 3 day water soak, 16 wks warm, 13 wks cold 55% 29. 25% 4 day water oak, 12 wks warm, 13 wks cold 49% 14. 5% 3% hydrogen peroxide 90 minute soak, 8 wks warm, 13 wks cold 45% 20% 6 day 10. 000 ppm citric acid soak, 6 wks warm, 10 wks cold 22% 24. 25%
Juniperus virginiana Eastern 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
J. virginiana seed treatments seed testing data 2002 -1962
Juniperus communis Seed Treatments • 15 minutes in H 2 SO 4 • 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
Juniperus osteosperma Seed 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 GA 3 to aerated water, germination is 64%
Juniperus monosperma Seed 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 GA 3 soak (250 ppm) before 30 day cold stratification had greatest germination rate
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
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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