Evaluations of Western
Prairie Clover and
Germination / Establishment
Considerations
Shaun Bushman USDA-ARS
Doug Johnson USDA-ARS
Kevin Connors USDA-ARS
Kishor Bhattarai Noble Foundation
1
Native Legumes – The Need is Great
Three legumes
Astragalus filipes
(basalt milkvetch)
Dalea ornata
(western prairie clover)
•
•
•
•
Dalea searlsiae
(Searl’s prairie clover)
Broad distribution – greater areas of use.
Grow in areas of relatively low precipitation.
Palatable to herbivores.
Amenable to mass seed production.
A Few Worries
ASSUMING GERMINATION AND ESTABLISHMENT - failed persistence of new
plantings or invasiveness:
- if the new planting is not locally adapted.
- if the maladapted traits in the new planting cause quick death.
- or if there is no ability of the new planting to change to local conditions.
- if a new planting survives and there is heterosis, and if that heterosis causes
invasion.
- if a new plant survives and there is outbreeding depression, and if that cannot be
overcome with natural selection.
- if climate change, site disturbance, or invasive weeds have changed things
enough to affect adaptation.
What is the likelihood of each if? Of a combination of if’s in one?
Should we worry
Ways of indicating the possibility of maladaptation, inbreeding depression,
outbreeding depression, and invasive potential.
i. Maladaptation: estimate correlation between common garden traits and
collection site environments. Make regression equation of significant
parameters. Conduct site transfer experiments.
ii. Inbreeding depression: observe vigor in common garden and withinpopulation genetic diversity with partial genome scan.
iii. Outbreeding depression: estimate genetically differentiated groups, make
crosses and evaluate progeny. Conduct site transfer experiments.
iv. Invasive potential: assume a broad distribution precludes invasiveness,
conduct crosses and test progeny in appropriate settings.
Species and distributions
Dalea ornata
Western prairie clover
Dalea searlsiae
Searls prairie clover
Species and Distributions
Astragalus filipes
Basalt milkvetch
Broad distribution assumes that
crossing with other species or
spreading would have occurred
naturally already, if at all.
Gene Flow History – D. ornata
Using DNA markers as genome scans:
 Deschutes River collections (blue) showed signs of differentiation from others
(gene flow barrier).
 John Day River collections (17, 20, 22) were more similar to ID and WA collections
than Deschutes collections.
 Non-Deschutes collections showed signs of substantial gene flow.
Signs of Local Adaptation – D. ornata
Original variables
Dry matter yield, Millville
Dry matter yield, Hyde Park
Inflorescence weight
No. of inflorescence, Hyde Park
No. of inflorescence, Millville
Plant height
Foliage diameter
Flowering date
PHEN1
-0.29
-0.10
0.26
0.48
0.29
-0.28
0.15
-0.85
PHEN2
-0.39
-0.71
-0.47
-0.58
-0.54
0.31
-0.37
0.41
Precipitation
Temperature
Elevation
CLIM1
0.39
-1.00
0.85
CLIM2
0.03
0.00
0.51
Flowering Date:
Positive correlation to temperature
Negative correlation to elevation
Earlier flowering = ↓ temp. & ↑ elev.
Range of flowering dates = 163-180
days after Jan 1st, or 17 day difference
in Utah plots.
Gene Flow and Local Adaptation – D. ornata
Flowering time discriminated the two genetic structures perfectly, but not any
other population groups.
So how important for survival and
adaptation is separation of the
Deschutes genetic group with it’s
later flowering?
We don’t know. At this point we are
releasing two germplasms.
Site transfer: plant O4 and O10 at all three sites.
Hypothesis: no differences in the local vs distal populations.
Gene Flow History – D. searlsiae
NW Utah collections were a
genetically differentiated group.
All others showed indications of
substantial gene flow.
Four NW Utah collections would
have been under lake Bonneville –
range expansion?
Signs of Local Adaptation – D. searlsiae
Original variables
Dry matter yield, Hyde Park
Dry matter yield, Millville
No. of inflorescence, Hyde Park
No. of inflorescence (2007), Millville
No. of inflorescence (2008), Millville
Inflorescence weight
Flowering time
Plant height
No. of stems
Foliage diameter
Acid detergent fiber
Neutral detergent fiber
Crude protein
PHEN1
0.5925
0.4497
0.4977
0.5572
0.2838
0.634
-0.2923
0.2846
0.2117
0.3862
0.1653
0.288
-0.3553
Elevation
Temperature
Precipitation
CLIM1
0.2573
-0.2829
0.8901
No trait has a very high
correlation. Precipitation
affects most of the traits
to a small extent.
Should it be considered?
Gene Flow History – D. searlsiae
Genetic distance was correlated
to precipitation
r = 0.43, P < 01.
S14, 17, and 1 are “officially” in the
Colorado Plateau yet show complete
gene flow and similar phenotypes with
western UT and eastern NV.
Gene Flow History – A. filipes
Northern and Southern extremes were
separate groups.
PC1
PC2
Elevation
-0.71**
0.36**
Longitude
-0.49**
0.11 ns
0.46**
-0.47**
ns
-0.14 ns
Min
0.25*
-0.35**
MM
0.28*
0.26*
Latitude
Max
-0.19
Higher elevation correlates
to lower PC1 loadings.
So higher elevation sites
might have:
Lower
Higher
biomass
CP
seed yield
winter mort.
# flowers
plant height
Will releases be able to survive
elevation ~400 m
Should we recommend not to mix low and
high elevation seed sources?
Phenotypic plasticity:
- Low elevation-derived plants had lower
mortality in common garden.
- High elevation-derived plants had higher
mortality in common garden.
NBR-1 from elevations 1,200 m – 1,600
m. Has great adaptive potential and
from areas of high gene flow.
elevation ~2000 m
Gene Flow and Local Adaptation – A. filipes
Site transfer: plant NBR-1 and #51 at
all four sites. Elevation gradient and
genetic structure gradient.
Hypothesis: no differences in the local
vs distal populations.
Planning for Persistence
In outcrossing plants with broad distribution, it is unknown:
•
•
•
If a new planting will be maladapted, better adapted, or no difference.
if a new planting will result in heterosis, outbreeding depression, or
no difference.
If there end up being any adverse effects, will they be extreme enough
that natural selection will not overcome them.
It is worth considering the magnitude of gene flow barriers and the magnitude
of local adaptation when using these data to determine appropriate plantings.
My opinion is that only extreme phenotype/climate correlations, and very
substantial genetic structures, are worth considering.
Site transfer experiments will help estimate how important each is.
Seed Production Potential
Predictions
D. ornata Group
9
22
20
Dp
17
4
25
19
14
23
16
21
6
3
8
2
5
7
15
13
11
12
1
Deschutes
other JD
other JD
Check
other JD
other
Deschutes
other
Deschutes
Deschutes
Deschutes
other
other
other
other
other
other
other
other
other
other
other
other
Infl. Weight
114.2 A
101.8 AB
99.4 AB
95.1 ABC
94.0 AB
86.1 ABC
83.4 ABCD
82.8 BCDEF
77.4 ABCDE
75.7 ABCDE
74.1 ABCDE
70.9 BCDEFG
66.1 BCDEFG
56.0 CDEFG
52.2 DEFGH
46.3 DEFGH
45.1 EFGH
44.6 EFGH
44.2 EFGH
43.4 FGH
36.8 GHI
27.3 HI
20.0 I
D. searlsiae
Ds-15
Ds-14
Ds-13
Ds-26
Ds-17
Ds-03
Ds-18
Ds-08
Ds-25
Ds-10
Ds-09
Ds-23
Ds-12
Ds-20
Ds-11
Ds-21
Ds-07
Ds-16
Ds-01
Ds-05
Group
other
other
other
other
other
other
other
other
other
other
other
NW Utah
NW Utah
other
other
NW Utah
other
NW Utah
other
other
Infl.
Weight
82.5
72.7
65.4
61.3
58.4
57.6
51.3
49.1
46.3
33.5
32.6
30.2
29.6
29.5
27.9
22.7
22.1
21.7
20.7
20.7
among
31%
within
69%
among
29%
within
71%
How not to get germination
Deschutes D. ornata (91% viable)
Ontario D. ornata (97% viable)
% hard
% hard
% germ
% germ
Unscarified seed gives 4-5% germination.
D. searlsiae similar, A. filipes slightly higher germination rate.
Currently testing the age of seed & scarification with all 3 species.
Further Seeding Tests
Greenhouse germination
tests:
1) depth,
2) age of seed,
3) Scarification.
Many Thanks
Great Basin Native Plant Selection and Increase
Project