FORAGE AND RANGE RESEARCH LABORATORY
PLANTS FOR THE WEST
U.S. Department of Agriculture
Agricultural Research Service
Forage and Range Research Laboratory
Effect of Seed Scarification and Seeding
Depth on Greenhouse Seedling Emergence
in Western Prairie Clover, Searls’ Prairie
Clover, and Basalt Milkvetch
Doug Johnson
Shaun Bushman
Tom Jones
Kevin Connors
PLANTS FOR THE WEST
FORAGE AND RANGE RESEARCH LABORATORY
USDA-ARS Forage and Range Research Lab (FRRL)
Logan, Utah
PLANTS FOR THE WEST
Our Mission:
Provide an array of improved
plant materials and management
alternatives for sustainable
stewardship of rangelands and
pastures in the western U.S.
Scientists:
Genetics/Plant Breeding (6)
Molecular Biology (4)
Physiology/Ecology (2)
FORAGE AND RANGE RESEARCH LABORATORY
Background
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• Thousands of acres burn each year in the Great
Basin and require revegetation.
• Many land managers prefer a mix of diverse
plant species for rangeland revegetation.
• Very few North American legumes are available
for rangeland revegetation in the Great Basin.
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Need for Native Legume Species
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Important for:
• Nitrogen fixation
• Seeding diversification
• Wildlife habitat and grazing
• Native pollinators
• Highways and roads
• Home xeriscaping
We targeted three legume species
native to western North America.
FORAGE AND RANGE RESEARCH LABORATORY
Basalt Milkvetch - Astragalus filipes (Asfi)
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• Wide spread
• Upright habit
• Creamy, showy flower
• Good seed production
• No reports of toxicity
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Western Prairie Clover - Dalea ornata (Daor)
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• Northern GB
• Upright habit
• Purple, showy flower
• Good seed production
• No reports of toxicity
FORAGE AND RANGE RESEARCH LABORATORY
Searls’ Prairie Clover - Dalea searlsiae (Dase)
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• Southern GB
• Upright habit
• Purple, showy flower
• Good seed production
• No reports of toxicity
FORAGE AND RANGE RESEARCH LABORATORY
Seedling Establishment: Critical Issue on Western Rangelands
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Legumes typically have problems with: Hard seed (impermeable
seed coat caused by physical and/or physiological mechanisms)
Hardseededness:
• Limits initial, uniform germination
• Spreads germination over a long time period
FORAGE AND RANGE RESEARCH LABORATORY
Example of Hard Seed Analyses
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Utah State Seed Lab (%)
Seedlot
Seed
absorbing
water
Daor SB 2010
Dase EK 2010
Asfi NBR-1 2010
11
3
4
Viable
hard seed
(Tz)
Total viable
73
84
95
84
87
99
FORAGE AND RANGE RESEARCH LABORATORY
Objective
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• Evaluate effects of seed scarification and seeding depth
on seedling emergence in Daor, Dase, and Asfi to
identify methods for enhancing seedling establishment
FORAGE AND RANGE RESEARCH LABORATORY
Six Seedlots Used in Study
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Daor
- SB 2009
- SB 2010
- SS 2009
- SS 2010
Dase
- EK 2010
Asfi
- NBR-1 2010
FORAGE AND RANGE RESEARCH LABORATORY
Three Seed Treatments
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1) Acid Scarification
• Soaked in concentrated sulfuric acid for 5 minutes
• Rinsed seeds in tap water for several minutes
• Dried the seeds
2) Sandpaper Scarification
• Seeds rubbed between two pieces of 120-grit sandpaper
3) No Treatment
FORAGE AND RANGE RESEARCH LABORATORY
Experimental Design
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Seedlots: Six
Seed Treatments: Acid-scarified, sandpaper-scarified, NT
Seeding Depth: 0.6 cm (¼ inch), 1.9 cm (¾ inch)
Design: Randomized complete block, 4 reps, 2 runs
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Procedures
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Planted 50 seeds per row, covered
seed with soil at two depths, and
kept well watered
Counted number of seedlings
12 times, Days 3-28: 2 runs
Corrected counts on PLS basis (TZ test)
FORAGE AND RANGE RESEARCH LABORATORY
ANOVA Summary
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Maximum Emergence (PLS Tetrazolium Basis)
Factor
df
F value
Depth
1
20.45
**
Seedlot (S)
5
263.45
**
Seed Treatment (T)
2
3,382.43
**
SXT
10
70.23
**
Depth X S
5
2.68
*
Depth X T
2
0.12
NS
Depth X S X T
10
2.21
*
NS = not significant, * = P < 0.05, ** = P < 0.01
Sign.
FORAGE AND RANGE RESEARCH LABORATORY
Main Effects for Maximum Emergence PLS-Tz.
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a
52
b
48
40
0.6 cm
1.9 cm
20
0
Planting Depth
100
Max. Emergence PLS-Tz. (%)
Max. Emergence PLS-Tz. (%)
60
80
82
a
b
72
60
Acid
40
Sand
NT
20
c
0
Seed Treatment
13
FORAGE AND RANGE RESEARCH LABORATORY
Seed Treatment Effects on Maximum Seedling Emergence PLS-Tz.
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120
100
ab
ab
abc
a
abc
bc
Max. Emergence PLS-Tz. (%)
c
d
80
d
e
Acid
Sand
NT
60
40
f
g
g
20
h
h
i
j
i
0
Daor SB
2009
Daor SB
2010
Daor SS
2009
Daor SS
2010
Dase EK Asfi NBR
2010
2010
FORAGE AND RANGE RESEARCH LABORATORY
Rate of Seedling Emergence (Maguire, 1962)
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Number of seedlings + . . . . . + Number of seedlings
Days to first count
Days to final count
FORAGE AND RANGE RESEARCH LABORATORY
Seed Treatment Effects on Rate of Seedling Emergence
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Rate of Emergence (#/day)
10
a
a
a
a
a
8
b
bc
cd
6
d
Acid
d
Sand
4
NT
2
e
g
fg f
f
h
i
i
0
Daor SB
2009
Daor SB
2010
Daor SS
2009
Daor SS
2010
Dase EK Asfi NBR
2010
2010
FORAGE AND RANGE RESEARCH LABORATORY
Conclusions
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• Daor, Dase, and Asfi have high levels of hardseed
• Seedlings of Daor and Dase emerged well at both
planting depths
• Scarification greatly improved emergence in Daor
and Dase, much less so for Asfi
• Scarification appears necessary to maximize
seedling emergence in Daor and Dase
FORAGE AND RANGE RESEARCH LABORATORY
Future
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Compare Results of Greenhouse Studies to
Actual Field Establishment
Collaborative field establishment studies with:
- Matt Horning (Clarno, Powell Butte, OR)
- Clint Shock/Erik Feibert (Ontario, OR)
FORAGE AND RANGE RESEARCH LABORATORY
Additional Greenhouse Studies
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Searls’ Prairie Clover
Sand
Clay/Sand
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Two Releases for Western Prairie Clover
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Majestic
Germplasm
Spectrum
Germplasm
Johnson, D.A., B.S. Bushman, K. Bhattarai, and K.J. Connors. 2011. Notice of release of Majestic
germplasm and Spectrum germplasm western prairie clover. Native Plants Journal 12: 249-256.
FORAGE AND RANGE RESEARCH LABORATORY
Acknowledgements
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Great Basin Native Plant Selection and Increase Project
FORAGE AND RANGE RESEARCH LABORATORY
PLANTS FOR THE WEST
U.S. Department of Agriculture
Agricultural Research Service
Forage and Range Research Laboratory
Doug Johnson
Phone: (435) 797-3067
Email:
doug.johnson@ars.usda.gov
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FORAGE AND RANGE RESEARCH LABORATORY
Combining Genetic/Ecological and Performance Considerations
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Genetics/Ecology:
• Genetic background
• Species compatibility
Field Performance:
• High seed production
• Vigorous seedlings
• Competitive ability
Plants that:
• Establish, compete, and persist
• Stabilize the site
• Have affordable, available seed
FORAGE AND RANGE RESEARCH LABORATORY
Two New Western Prairie Clover Releases: Majestic, Spectrum
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1) Made seed collections
across 25 sites
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Common-Garden Field Data
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2) Conducted Evaluations at
Two Common Garden Sites
• Flowering date
• June biomass
• Plant height
• Plant vigor score
Two years of data
collection
• Seed yield
• Fall regrowth
• Forage quality
FORAGE AND RANGE RESEARCH LABORATORY
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3) Genetic Diversity Structure Determined
For The Three Legume Species
• DNA procedures (AFLP) were
used to determine the genetic
diversity structure for each of
the three legume species.
• Results from DNA analysis
allowed grouping of collections
with similar genetic background.
FORAGE AND RANGE RESEARCH LABORATORY
Majestic Germplasm Western Prairie Clover
PLANTS FOR THE WEST
Johnson, D.A., B.S. Bushman, K. Bhattarai, and K.J. Connors.
2011. Notice of release of Majestic germplasm and
Spectrum germplasm western prairie clover. Native Plants
Journal 12: 249-256.
Grower partners: BFI Native Seeds, L&H Seed, Ron Bitner/Paul Beckman
FORAGE AND RANGE RESEARCH LABORATORY
Spectrum Germplasm Western Prairie Clover
PLANTS FOR THE WEST
Johnson, D.A., B.S. Bushman, K. Bhattarai, and K.J. Connors.
2011. Notice of release of Majestic germplasm and
Spectrum germplasm western prairie clover. Native Plants
Journal 12: 249-256.
Grower partners: BFI Native Seeds, L&H Seed