Supplementary Information 1: Phenotypic differences (height, total leaf area, individual tiller biomass)
between 4 common genotypes of A. gerardii as measured in the field (2008) at the Konza Prairie
Biological Station. Values are mean ± SE (* p <0.001).
May
Genotype n
A
112
B
62
C
40
D
19
Height (cm)*
20.804 ± 0.694
21.275 ± 1.017
21.83 ± 1.177
16.0219 ±
1.141
Total leaf area (cm2)
Ind Biomass (g)
15.637 ± 1.084
0.108 ± 0.006
16.637 ± 1.694
0.114 ± 0.009
19.026 ± 2.117
0.128 ± 0.012
15.215 ± 2.931
0.105 ± 0.017
June
Genotype n
A
112
B
62
C
40
D
19
Height (cm)*
38.618 ± 1.373
36.762 ± 1.669
41.155 ± 2.033
38.357 ± 2.713
Total leaf area (cm2)*
42.236 ± 3.349
42.791 ± 5.163
47.855 ± 5.255
40.816 ± 6.095
Ind Biomass (g)*
RGR
0.338 ± 0.031
0.772 ± 0.114
0.343 ± 0.048
0.684 ± 0.145
0.390 ± 0.048
0.880 ± 0.135
0.325 ± 0.056
0.798 ± 0.274
Supplemental Information 2: Measured phenotypic traits of A. gerardii genotypes grown alone, in intra,
and intergenotypic competition under low and high light conditions. Total biomass (above + below, top
graphs), total aboveground biomass (middle graphs), and root:shoot ratio (bottom graphs) traits are
presented. See Table 1 for corresponding ANOVA results.
Supplemental Information 3: Measured phenotypic traits of A. gerardii genotypes grown alone, in intra,
and intergenotypic competition under low and high light conditions. July:August relative growth rate
(top), reproductive tiller count (middle), and presence of bolting flower stalk (bottom) traits are presented.
See Table 1 for corresponding ANOVA results.
Supplementary Information 4: Mean (± SE) aboveground individual tiller biomass (g) and number of new
vegetative tillers produced by A. gerardii genotypes grown in inter-genotypic (eg. AB) competition under
high light conditions with either low (-) or high (+) water (W) and nitrogen (N). These two traits have
significant water by nitrogen by genotype interaction effects (see Table 1 for ANOVA results, letters
indicate significantly different groups).
W
+
+
+
+
+
+
+
+
N
+
+
+
+
+
+
+
+
Genotype
A
B
C
D
A
B
C
D
A
B
C
D
A
B
C
D
Individual tiller biomass (g)
2.207 ± 0.242ab
2.704 ± 0.182b
1.494 ± 0.186a
2.622 ± 0.259b
2.727 ± 0.209b
2.414 ± .162b
1.608 ± 0.204a
1.927 ± 0.278ab
3.516 ± 0.319f
3.743 ± 0.359f
2.392 ± 0.362e
3.663 ± 0.535f
3.904 ± 0.424f
3.762 ± 0.378f
3.144 ± 0.409f
5.247 ± 0.707g
Number of vegetative tillers
0.467 ± 0.274c
1.333 ± 0.652cd
1.467 ± 0.274cd
0.933 ± 0.419c
1.667 ± 0.386cd
1.533 ± 0.322cd
2.133 ± 0.363d
2.667 ± 0.485d
1.533 ± 0.413i
2.400 ± 0.456i
2.667 ± 0.386ij
2.933 ± 0.473j
0.267 ± 0.153h
1.800 ± 0.355i
1.933 ± 0.316i
3.000 ± 0.276j
Supplementary Information 5: Effects of genotype identity (G) and resources (W, water, N, nitrogen; R,
both water and nitrogen) on the yield-suppression coefficient (S) of A. gerardii individuals grown in
inter-genotypic competition under the low and high light treatments (see text for details). Yieldsuppression coefficients were calculated using root biomass, total aboveground biomass, and total
biomass (root plus tiller) biomass. Separate ANOVAs were conducted for the low and high light
treatments. Significant (p ≤ 0.05) F-statistics and p-values are bolded.
High light
Low light
Root biomass
Aboveground
biomass
F
p
F
p
G
0.83
0.48
4.63
R
0.90
0.45
GxR
0.97
G
Total biomass
F
p
0.00
3.47
0.02
1.46
0.23
1.17
0.28
0.41
1.06
0.40
1.29
0.28
0.00
0.06
2.08
0.10
1.02
0.39
W
4.61
3.52
N
GxW
5.33
1.02
0.02
0.38
10.33
5.2
1.7
0.00
0.02
0.15
15.00
10.54
2.07
0.00
0.00
0.10
GxN
0.87
0.46
1.88
0.13
0.57
0.63
GxWxN
2.91
0.03
9.22
0.00
6.25
0.00
Supplementary Information 6: Mean and standard error values of yield-suppression coefficients (S)
calculated using root, above and total biomass for each genotype grown under low and high light
conditions. Genotype hierarchies based on S values. Genotypes with the highest S values are considered
the most competitively dominant. Bolded values are significantly different (p ≤ 0.05) from each other
based on ANOVA (see Supplemental Information 5).
High Light
Low light
Genotype
A
B
C
D
A
B
C
D
S
Competitive hierarchy
Root
Above
Total
Root
Above
Total
0.84 ± 0.11
1.70 ± 0.33
1.47 ± 0.69
1.49 ± 0.22
0.49 ± 0.03
0.66 ± 0.03
0.54 ± 0.05
0.56 ± 0.02
0.73 ± 0.11
1.49 ± 0.23
0.98 ± 0.20
1.30 ± 0.17
0.99 ± 0.13
0.80 ± 0.06
0.70 ± 0.06
0.88 ± 0.10
0.75 ± 0.11
1.49 ± 0.22
0.98 ± 0.13
1.35 ± 0.15
0.65 ± 0.04
0.71 ± 0.03
0.62 ± 0.05
0.68 ± 0.04
B
D
C
A
B
D
C
A
B
D
C
A
A
D
B
C
B
D
C
A
B
D
A
C
Supplementary Information 7: Relative Yield Total (RYT) for each pairwise genotype combinations.
RYT values greater than 1.0 indicate genotypes make demands on different resource units (Taylor and
Aarssen 1990). All RYT values are significantly different than 1.0 based on t-test analyses.
light
water
nitrogen
combo
RYT root
RYT above
RYT total biomass
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
AB
AC
AD
BC
BD
CD
AB
AC
AD
BC
BD
CD
AB
AC
AD
BC
BD
CD
AB
AC
AD
BC
BD
CD
AB
AC
AD
BC
BD
CD
AB
AC
AD
BC
BD
CD
2.042
1.535
2.943
2.795
2.184
2.128
2.030
1.236
3.151
1.753
2.679
2.705
2.019
2.067
1.866
1.792
1.758
1.746
1.857
2.101
1.977
1.881
2.048
1.957
1.965
1.527
2.075
1.937
2.030
1.703
2.058
2.264
1.978
2.140
1.770
1.814
1.955
1.896
2.721
2.542
2.107
2.157
2.076
1.276
2.935
1.834
2.444
2.408
1.927
2.017
2.237
2.029
1.944
2.019
1.623
2.001
1.608
1.807
1.803
1.579
1.599
1.562
1.689
2.011
1.997
1.873
1.947
1.586
1.848
1.724
1.669
1.958
1.981
1.771
2.792
2.620
2.131
2.149
2.071
1.285
3.009
1.789
2.526
2.517
1.964
2.025
2.092
1.940
1.875
1.918
1.690
2.029
1.696
1.828
1.866
1.687
1.717
1.549
1.785
1.987
2.004
1.805
1.967
1.805
1.845
1.851
1.696
1.912
High light
Low light
Supplementary Information 8: Effects of genotype combination (AB, AC, AD, BC, BD, CD) and
resources (W, water, N, nitrogen; R, both water and nitrogen) on the relative yield total (RYT) of A.
gerardii individuals under the low and high light treatments. RYTs were calculated using belowground
(root biomass), aboveground (total vegetative tiller biomass), and total biomass (below plus aboveground)
biomass. Separate ANOVAs were conducted for the low and high light treatments. Significant (p ≤ 0.05)
F-statistics and p-values are bolded.
RYT
RYT
belowground
RYT aboveground
total
F
p
F
p
F
p
Geno combo
0.02
0.96
2.36
0.10
0.05
0.76
2.62
0.36
Resource
2.88
0
0.03
0.86
Geno combo x R
Geno combo
W
N
Geno combo x W
Geno combo x N
Geno combo x W x N
0.87
1.07
0.09
4.31
1.11
1.34
2.15
0.51
0.38
0.80
0.04
0.36
0.25
0.05
0.79
0.25
1.66
3.99
1.11
0.50
1.78
0.56
0.94
0.20
0.05
0.36
0.78
0.11
0.83
0.13
1.02
1.33
1.17
0.65
1.60
0.54
0.98
0.31
0.25
0.32
0.65
0.15