Genecology and Seed Transfer
Guidelines for Bluebunch Wheatgrass
(Pseudorogneria spicata)
Brad St.Clair
USDA FS Pacific Northwest Research Station, Corvallis, OR
R.C. Johnson
USDA ARS Western Regional Plant Introduction Station, Pullman, WA
Nancy Shaw
USDA FS Rocky Mountain Research Station, Boise, ID
Photo: Berta Youtie
2011 Great Basin Native Plant Selection and Increase Project Annual Meeting
Genecology and Adaptation
• Genecology: the study of interspecific genetic variation of
plants in relation to environments (Turresson 1923)
• Seeks correlations between “plant type” and “habitat type”
• Genetic variation is studied using common garden tests
• Adaptation: the evolutionary process whereby a population
becomes better suited to its environment
• Consistent correlations between a character and
environmental factors at a seed source is indicative of
adaption; the same form occurs in similar environments
• Evidence for adaptation: (1) populations vary, (2) population
means for traits are correlated with source environments,
(3) relationship makes sense
Objectives
1. Explore genetic variation among bluebunch
wheatgrass populations from a wide range of
source environments in the inland West
2. Relate genetic variation to environmental
variation at source locations
3. Develop seed transfer guidelines
4. Compare native variation to common cultivars
of bluebunch wheatgrass
Goal: adapted, diverse plant populations
for restoration
Population Sampling
Collections from:
127 populations
2 families per population
5 cultivars
Hanford Reserve, Central Washington
Common Garden Tests
Planted at three common garden test sites in 2006:
Central Ferry, WA – warm, dry
Lucky Peak Nursery, ID – cooler, dry
Pullman, WA – cold, wet
6 replications, 1 plant per family per rep
4,752 total plants
Transplanting Bluebunch Wheatgrass,
Lucky Peak, Fall 2006
Measurements
Eighteen traits measured in 2007 & 2008:
• Size – biomass, crown width, height, regrowth biomass
• Fecundity – inflorescence number
• Phenology – heading, anthesis, seed maturation, germination
• Morphology – plant form, leaf width, leaf length, leaf color,
leaf pubescence, culm length, spike length, spikelet number,
awn length
Analyses
• ANOVA
– Differences among test sites and between years
– Population and family component of variances
– Interactions: genotype x site and genotype x year
• Also evaluated by correlations among test sites and between years
• Correlations among traits/Principal Component Analysis
– Individual traits
– PCA to reduce the number of traits to a few uncorrelated traits
• Relationship of traits to environment
– Correlations
– Regressions
• Maps of genetic variation using GIS
• Overlap maps of PCA to characterize areas that are
similar in adaptive traits/environments
• Characterization of cultivars
– Mean and variances
Trait means at three test sites
(average of 2007 and 2008 data)
Trait
Central Ferry
Lucky Peak
Pullman
Dry wt (g)
100
84
41
Crown width (cm)
9.3
7.4
8.4
Inflorescence no.
100
120
43
Leaf form (ht:width ratio)
41
39
33
Leaf color (1-9 yellow to dark green)
3.3
3.0
2.9
Leaf pubescence (1-9 none to much)
3.9
4.6
4.1
Plant form (1-9 prostrate to upright)
6.1
6.2
6.5
Awn length (1-9 none to long)*
4.6
4.6
4.7
Heading date (Julian days)
133
136
143
Bloom date (Julian days)
146
149
162
Maturity date (Julian days)
184
190
199
Germination rate (Days to 50%)
5.0
6.1
4.8
Size and flowering: CF > LP >> PU
Leaf width: CF < LP < PU
Phenology: CF < LP < PU
* Non-significant
Trait means in 2007 compared to 2008
(average of three test sites)
Trait
2007
2008
Dry wt (g)
42
111
Crown width (cm)
5.5
11.4
Inflorescence no.
28
150
Leaf form (ht:width ratio)*
38
38
Leaf color (1-9 yellow to dark green)
3.2
2.9
Leaf pubescence (1-9 none to much)
4.8
3.5
Plant form (1-9 prostrate to upright)*
6.3
6.3
Awn length (1-9 none to long)
4.6
4.7
Heading date (Julian days)
133
141
Bloom date (Julian days)
148
157
Maturity date (Julian days)
189
192
Size and flowering: 2007<2008
Phenology: 2007 < 2008
Leaf pubescense: 2007 > 2008
Leaf color: 2007 > 2008
* Non-significant
Variation among populations and families
• Generally large levels of
population variance in 2007
% Location
Variance
Trait
CF
LP
PU
Dry wt
48
21
37
•Less so in 2008 (more “noise”
in data; e.g., crown width)
Crown width
33
23
32
Inflorescence no.
46
36
34
Leaf form
34
39
19
• Low variation among families
within populations (2%)
Leaf pubescence
37
28
42
Leaf color
33
35
12
Plant form
17
30
7
Awn length
45
58
49
Heading date
37
30
19
Bloom date
22
44
27
Maturity date
17
18
10
• No test site showed greater
population differences in all
traits
(2007 data)
Interactions of populations with test sites
Does population performance depend upon test site?
Correlations between test sites
Dry wt:
CF w/ LP
CF w/ PU
LP w/ PU
Heading date:
CF w/ LP
CF w/ PU
LP w/ PU
Leaf ratio:
CF w/ LP
CF w/ PU
LP w/ PU
Crown width:
CF w/ LP
CF w/ PU
LP w/ PU
2007
0.83
0.77
0.79
2008
0.80
0.75
0.81
0.83
0.68
0.66
0.50
0.38
0.55
0.85
0.84
0.85
0.85
0.81
0.85
0.83
0.78
0.74
-0.28
0.14
-0.12
Answer: No. In general, little GxE
(Test Site)
- Few significant interactions
- Traits are strongly correlated among
sites
- A few traits not correlated among
sites in 2008 (crown width, culm length)
Interactions of populations with years
Does population performance depend upon year of evaluation?
Correlations between years
Dry wt:
CF
LP
PU
Heading date:
CF
LP
PU
Leaf ratio:
CF
LP
PU
Crown width:
CF
LP
PU
r
0.77
0.75
0.88
0.66
0.59
0.42
0.81
0.84
0.80
0.02
-0.05
0.10
Answer: No. In general, little GxYear
- Few significant interactions
- Traits are mostly strongly correlated
among years
- A few traits not correlated between
years (crown width, regrowth)
Correlations among traits
Correlations among size traits:
Dry wt w/ crown width (2007) 0.86
Dry wt w/ inflorescence no.
0.77
Dry wt w/ height
0.39
Correlations among phenology traits:
Heading w/ bloom
0.73
Heading w/ maturation
0.34
Bloom w/ maturation
0.51
Other traits not strongly correlated
Correlations between other traits:
Dry wt w/ heading
-0.12
Heading w/ leaf ratio
-0.15
Heading w/ leaf color
0.08
Some traits are correlated.
Other traits appear to be
independent of each other.
Suggests that PCs may be
easily interpretable.
Principal Component Analysis
PC
Eigenvalue
Percent
variation
explained
Cumulative
percent
variation
1
12.42
30.3
30.3
Larger size, more fecund
2
5.95
14.5
44.8
Later phenology, taller in 2007
3
3.52
8.6
53.4
Narrow leaves, more upright
4
2.40
5.9
59.2
--
5
2.16
5.3
64.5
--
6
2.00
4.9
69.4
--
Interpretation
Correlations of first three principal components with individual traits
Trait
PC1
PC2
PC3
Dry wt
0.93
-0.14
-0.15
Height07
0.56
0.50
0.34
Inflorescence no.
0.76
-0.29
-0.16
Leaf color
0.57
0.06
-0.42
Leaf pubescence
-0.39
-0.28
0.12
Plant form
-0.47
0.09
0.62
Leaf form
-0.12
-0.07
0.58
Heading date 07
-0.09
0.79
-0.21
Bloom date 07
-0.20
0.84
0.02
Maturity date 07
-0.23
0.44
-0.35
Germination rate
-0.21
0.39
0.15
Percent of trait
variation in PC
30%
15%
9%
PC1 = greater vigor, size, fecundity, greener, more prostrate
PC2 = later phenology, taller
PC3 = narrower leaves, more upright
Correlations of traits with climate
PC1
Dry wt
PC2
Heading
date
PC3
Leaf
form
Annual temp
0.21
0.28
-0.47
-0.36
0.33
0.44
Warmest month
temp
0.17
0.22
-0.43
-0.33
0.35
0.48
Coldest month
temp
0.30
0.37
-0.49
-0.37
0.26
0.37
Temp
differential
-0.26
-0.31
-0.09
-0.09
0.43
0.53
Annual precip
0.29
0.33
0.10
0.07
-0.46
-0.48
Summer precip
0.32
0.33
0.11
0.11
-0.54
-0.52
Aridity
0.00
0.07
-0.51
-0.36
0.42
0.58
Precip as snow
0.20
0.27
0.22
0.18
-0.49
-0.47
Latitude
0.26
0.33
-0.56
-0.32
0.34
0.11
Elevation
-0.10
-0.20
0.28
0.37
-0.58
-0.40
Climate
Warmer, higher precip,
lesser temp differentials,
greater precip as snow
Lower temps, less aridity Warmer, greater aridity,
greater seasonal temp
differentials, and less
precip as snow
Regressions of trait on climate and geography
R2 from
regression
Regression equation
PC1
0.37
3.67-0.467*TAVSP-0.121*PPTWT+0.03*PPTSP-0.03*2SHM
PC2
0.35
-7.22-0.43*TMINWT+0.38*TAVSM-0.02*SHM
PC3
0.28
2.33-0.17*MSP
Dry wt
0.47
212.5+7.36*TMINWT+0.10*PPTSP-0.21*SHM
Leaf form
0.38
38.45-0.02*PPTWT+0.045*SHM
Heading date
0.41
131.75-0.06*NFFD
Trait
Maps of genetic variation in PC1 and dry weight
Blue = larger, more vigorous plants, more
flowers, greener, more prostrate
Red = smaller, less vigorous plants, fewer
flowers, less green, less prostrate
Blue = larger plants
Red = smaller plants
Larger plants from areas of higher temperatures and precip,
lesser seasonal temperature differentials, more precip as snow
Mountains vs deserts / High deserts vs low deserts
Maps of genetic variation in PC2 and heading date
Red = earlier phenology
Blue = later phenology
Red = earlier heading
Blue = later heading
Earlier phenology from areas of higher
temperatures, greater aridity
In particular, low deserts
Maps of genetic variation in PC3 and leaf width
Red = narrow leaves, upright plants
Blue = wider leaves, upright plants
Red = narrow leaves
Blue = wider leaves
Narrower leaves from areas of higher temperatures, greater
aridity, and greater seasonal temperature differentials
Deserts including high deserts
Recommended Seed Zones
Ecoregion
Number
of zones
Colors
Comments
Columbia Plateau
4
Yellow to mid-blue
May include adjacent green zones.
Blue Mountains
3
Lt blue to dark blue
Green zones may be included with
Columbia Plateau.
Northern Basin & Range
3
Lt blue to dark blue
May include adjacent blue areas.
Snake River Plain
3
Green to mid-blue
Dark blue areas may be included with
Northern Rockies zones
Central Basin &Range
5
Yellow to dark blue
Not sure if bluebunch exists in 2 zones
Comparisons of native collections with cultivars
Noncultivars
Anatone
Goldar
P-7
Whitmar
Secar
Dry wt
76
151
154
160
131
201
Crown width
8.4
9.2
9.0
9.8
9.4
9.7
Inflorescence no.
88
199
172
159
168
201
Leaf form
38
39
32
41
34
42
Leaf color
3.1
3.3
3.5
3.6
3.7
3.4
Leaf pubescence
4.2
4.3
4.2
4.0
4.2
2.9
Plant form
6.3
5.7
5.5
5.7
5.4
6.5
Awn length
4.6
1.9
3.9
1.7
1.1
6.2
Heading date
137
136
1.40
139
138
142
Bloom date
152
152
150
154
157
154
Maturity date
191
190
192
192
189
192
Trait
Cultivars are more vigorous in test environments. Selection works.
Cultivars are variables w.r.t. leaf width, phenology, and awn length.
Secar is most different = Elymus wawawaiensis
Conclusions
• High levels of population variation in many traits
• Correlations with climate are fairly strong
• Relationships make sense from an adaptation perspective
–
–
–
–
Larger, more vigorous plants come from populations located in wetter, mountainous
regions without large seasonal temperature differentials
Plants with later heading and anthesis dates come from populations located in
colder, less arid climates
Plants with narrow leaves come from populations located in warmer, more arid
climates, particularly in the summer
Plants with more leaf pubescence come from populations located in drier climates
• Thus, strong evidence for adaptively significant genetic variation
• Seed zones are proposed that follow these gradients in
traits/climates, but be cautious about transfers between Level 3
ecoregions.
Climate matters
Thanks to many folks who
contribute to seed collections
Procedure
1.
2.
3.
4.
5.
6.
7.
Sample populations from many diverse environments
Measure traits in a common environment
ANOVA to explore sources of variation and
interactions; particularly interested in traits with high
population variation
Principal component analysis to reduce number of traits
Correlations and regressions to explore relation of
traits to climate
Use GIS and regressions to produce maps of genetic
variation
Overlap PC maps to delineate areas of similar
populations = seed zones
Correlations of traits with climate
Climate
PC1
Dry wt
PC2
Leaf
form
PC3
Heading
date
Annual temp
0.07
0.17
0.61
0.44
-0.22
-0.36
Warmest
month temp
0.01
0.12
0.62
0.48
-0.16
-0.33
Coldest
month temp
0.19
0.27
0.55
0.37
-0.26
-0.37
Temp
differential
-0.44
-0.31
0.50
0.53
-0.17
-0.09
Annual
precip
0.42
0.35
-0.43
-0.42
-0.11
0.07
Summer
precip
0.46
0.35
-0.48
-0.46
-0.12
0.11
Aridity
-0.15
0.01
0.69
0.55
-0.22
-0.36
Precip as
snow
0.35
0.27
-0.52
-0.47
-0.02
0.18
Latitude
0.26
0.33
0.34
0.11
-0.56
-0.32
Elevation
-0.10
-0.20
-0.58
-0.40
0.28
0.37
Higher precip, lesser temp Higher temps, greater
Lower temps, less aridity
differentials, greater precip aridity, lower seasonal
as snow
temp differentials, and less
precip as snow