Seed Cleaning & Testing
GBNPSIP
February 2008
FS National Seed Laboratory
Vacuum line to
collect dust
Westrup
Brush
Machine
Extracts seeds from
fruits and makes seeds
flowable
Turning brushes rub seeds
Against the shell (wire screen)
Wire
shell
The machine is
open for
demonstration
Penstemons required courser
shell #10 and higher
speed (9 on a 1-12 scale)
Agoseris glauca (pale agoseris)
rough seed before
extraction and singularization in the
brush machine
Grass seed found when scalping trash
from Agoseris seed
Contaminating
grass seeds
Agoseris
seeds
Cleaning seeds to high purity helps
find these contaminants
Species
Extraction
machine
Scalping
Screens
Sieving
Screens
Aspirator
pressure
Blower
pressure
Agoserus glauca Pale agoserus
B19 S 3
6 rd
6 x 20
.02
1.0
Astragulus filipes Basalt milkvetch
Tumbler
7.5 rd
14 x 14
.04
n/a
Balsamorhiza sagitta Arrowleaf balsomroot
Tumbler
8 rd
6x9
.04
1.0
Crepis acuminata Tapertip hawksbeard
B19 S3
8 rd
1/23
.01
n/a
Eriogonum heracleoides
Parsnipflower buckwheat
B19 S2
8 rd
6 x 30
.02
n/a
Eriogonum umbellatum Sulfurflower
buckwheat
B19 S2
8 rd
n/a
.04
n/a
Lomatium distichum Fernleaf biscuitroot
B19 S2
22rd
n/a
.02
1.0
Lomatium grayi Gray biscuitroot
B19 S2
22 rd
n/a
.02
1.0
Lomatium triternatum Nineleaf biscuitroot
B19 S2
22 rd
n/a
.02
1.0
Penstemon acuminatus Sand penstemon
B10 S6
20 rd
6.5 rd
n/a
.04
n/a
Penstemon deustus Scabland penstemon
B10 S9
20 rd
20 x 20
n/a
.04
1.0
Sphaeralcea munroana Munro’s
globemallow
B19 S3
8 rd
1/19
1/21
.03
n/a
Heavier good
seeds
Insect hole
Lighter insect
damaged seeds
Lomatium seeds separated in the column blower
LODI 26
In d iv id u a l s e e d w e ig h t
Larger diameter light (18L) seed weigh
the same as smaller diameter heavy (16H)
seed
0.03
0.025
16H
0.02
16L
0.015
18H
0.01
18L
0.005
0
1
2
3
4
5
6
7
Individual seed number
8
9
10
Why it is necessary to size
Seed to remove lighter
damaged seed
Probe
Sample holder
Measuring water activity Aw
is the last step in cleaning
the seeds
Meter
Water
Activity
Meter
Hygrometer measuring water activity (Aw) of seeds in a covered box
New Method for Monitoring Seed Moisture:
Equilibrium Relative Humidity
ERH Line Fit Plot
0.16
0.14
0.12
mc
0.1
mc
0.08
Predicted mc
0.06
0.04
0.02
0
0
0.2
0.4
0.6
Equilibrium Relative Humidity
0.8
Germination Studies
(Continued)
• Started testing all species supplied to the
NSL.
• Lomatium spp have been supplied in
adequate numbers to get a pretty good
picture of what the protocol will be.
– Lomatium grayi
– L. triternatum
– L. dissectum
19 lots, 266 tests
13 lots, 182 tests
41 lots, 811 tests
– 1,259 test total for Lomatium dissectum
Lomatium triternatum Germination
7 seed lots 30+% germination
60
Germination Percentages
50
40
30
20
10
0
10-30
10-20
10
5-30
Germ
i nati o
nC
5-20
L5-10
ondi t
io
ns
D5-10
28
No days
strat
Lomatium grayi germination
12 lots 50+% germination
80
60
Germination
Percentages
40
20
0
10-30
10-20
10
5-30
5-20
Germination Conditions
28 days
No strat
L5-10
D5-10
Lomatium dissectum Germination
11 seed lots 50% germ ination or better
70
60
Germination
Percentage
50
40
30
20
10
0
70 days
56 days
49 days
10
42 days
L 5-10
Germination condition
D 5-10
Stratification
Lomatium Germination Summary
• Germination will be at 10oC or less
• Light is not inhibitory, may assist
• L. grayi, L. triternatum will be easiest to
germinate
• L. dissectum requires very low germination
temperature or long strat period
– Almost no germ w/o strat, very low germ w/ 28 days
strat
– Germination starts in strat at 56 and 70 days
– What is the difference between strat and germ at 5oC
– Will the plants actually germinate at 5oC?
Germination Studies 2008
• Should have a final answer on Lomatium
• Will expand to several more species
– Seed lots are on the way to the lab
– Have now acquired 10 new germinators
• Sufficient capacity to explore lots of temperatures
– Have worked out our procedures were we can
be more efficient.