Appendix 6. Data on Helianthus parental and hybrid performance
Data on Helianthus included in the meta-analysis are from a long-term experimental investigation of H.
annuus ssp. texanus, a natural hybrid lineage derived from H. annuus ssp. annuus x H. debilis. All three
taxa have an annual life history. Data on parental and hybrid performance were collected in six
common gardens planted in 2003, 2007, and 2011 near Austin, Texas USA; this site is within the
hypothesized historical range expansion of H. annuus putatively triggered by hybridization with H.
debilis. Data from the 2003 common gardens are reported in Whitney et al. (2006, 2010) while data
from the two remaining years are currently unpublished but are presented below (Table A5). In the
meta-analyses reported in the current manuscript, we compare the hybrid H. a. texanus to H. a. annuus,
which is the weedier and more invasive parent (see Whitney et al. 2006, 2010).
Methods for planting and trait measurements were similar across the three years and are generally
described in Whitney et al. (2006, 2010). Briefly, in each year, seeds of hybrids and parents were
germinated in peat pots in the greenhouse, and seedlings were then transplanted to the field at 3-4
weeks of age. Traits measured included seed set, plant volume in cm3, and plant longevity as the
number of days between transplanting and death (corresponding to “fecundity”, “size”, and “survival” in
the meta-analyses reported in the current manuscript).
Table A5. Helianthus hybrid and parental performance data from one common garden in 2007 and
three common gardens in 2011. Site codes: LBJ = Lady Bird Johnson Wildflower Center, Austin, TX, USA;
BFL = Brackenridge Field Laboratory, Austin, TX, USA. Abbreviations: BC = backcross; SD = standard
deviation; N = sample size (number of plants). In the numbering system indicating backcross generation,
whole numbers refer to adult plants and fractions refer to seeds, so BC4.5 refers to plants germinated
from seeds produced by fourth generation adult plants.
Trait
Year
Site
Garden ID
Taxon
Hybrid class
Mean
SD
Number viable seeds
2007
LBJ
LBJ2007
H. annuus ssp. texanus
wild hybrid
1196.1
2396.7
100
artificial hybrid
BC1
454.6
817.7
100
artificial hybrid
BC4.5
1179.4
2020.7
200
H. annuus ssp. annuus
n/a
1193.9
1904.2
100
H. annuus ssp. texanus
wild hybrid
3931.8
3141.1
50
artificial hybrid
BC1
1114.0
1098.1
49
artificial hybrid
BC7.5
4916.2
4707.8
100
H. annuus ssp. annuus
n/a
4479.6
3190.2
140
H. annuus ssp. texanus
wild hybrid
4091.5
4292.4
50
artificial hybrid
BC1
733.4
790.2
50
artificial hybrid
BC7.5
4113.1
3815.1
99
H. annuus ssp. annuus
n/a
3222.0
2815.6
140
artificial hybrid
BC7.5
8326.0
5578.1
100
H. annuus ssp. annuus
n/a
7732.8
5650.7
90
H. annuus ssp. texanus
wild hybrid
70.5
103.6
86
artificial hybrid
BC1
75.2
85.2
91
artificial hybrid
BC4.5
95.7
193.7
186
H. annuus ssp. annuus
n/a
173.2
345.5
93
H. annuus ssp. texanus
wild hybrid
273.2
117.4
50
artificial hybrid
BC1
195.7
68.8
50
artificial hybrid
BC7.5
219.2
105.0
100
H. annuus ssp. annuus
n/a
292.8
106.6
140
H. annuus ssp. texanus
wild hybrid
292.0
140.0
50
artificial hybrid
BC1
166.5
87.6
50
artificial hybrid
BC7.5
219.8
120.1
95
H. annuus ssp. annuus
n/a
257.1
121.4
134
artificial hybrid
BC7.5
385.5
163.3
99
H. annuus ssp. annuus
n/a
463.8
199.2
88
2011
2011
Plant volume (cm3)
LBJ
LBJ
LBJ2011A
LBJ2011B
2011
BFL
BFL2011
2007
LBJ
LBJ2007
2011
2011
2011
LBJ
LBJ
BFL
LBJ2011A
LBJ2011B
BFL2011
N
Table A5 continued. Helianthus hybrid and parental performance data from one common garden in
2007 and three common gardens in 2011. Site codes: LBJ = Lady Bird Johnson Wildflower Center,
Austin, TX, USA; BFL = Brackenridge Field Laboratory, Austin, TX, USA. Abbreviations: BC = backcross; SD
= standard deviation; N = sample size (number of plants).
Trait
Year
Site
Garden ID
Taxon
Hybrid class
Longevity (days)
2007
LBJ
LBJ2007
H. annuus ssp. texanus
wild hybrid
117.8
39.7
100
artificial hybrid
BC1
133.7
32.2
100
artificial hybrid
BC4.5
129.1
30.0
200
H. annuus ssp. annuus
n/a
133.9
28.4
100
H. annuus ssp. texanus
wild hybrid
157.0
25.4
50
artificial hybrid
BC1
151.7
15.2
50
artificial hybrid
BC7.5
145.4
13.4
100
H. annuus ssp. annuus
n/a
154.4
16.2
140
H. annuus ssp. texanus
wild hybrid
154.4
20.3
50
artificial hybrid
BC1
148.2
15.4
50
artificial hybrid
BC7.5
136.4
28.2
99
H. annuus ssp. annuus
n/a
141.2
31.1
140
artificial hybrid
BC7.5
132.9
16.4
100
H. annuus ssp. annuus
n/a
137.3
16.4
90
2011
2011
2011
LBJ
LBJ
BFL
LBJ2011A
LBJ2011B
BFL2011
Mean
SD
N