Return of the Native: a Look at Select
Accessions of North American Lewis Flax
Stanley G. Kitchen
perennial blue flax for traits associated with stand persistence, commercial seed production, and seedling establishment. Results will be used to develop native flax releases for commercial seed production and for restoration
plantings.
Abstract—Lewis flax (Linum lewisii) is a widely distributed
perennial forb in the Western United States. I compared the
performance of native Lewis flax accessions with that of the European cultivar ‘Appar’. In common garden studies, significant
differences in survival, vigor, rust resistance, and seed production were observed among ‘Appar’ and 14 Lewis flax accessions.
Some native Lewis flax accessions compared favorably to ‘Appar’
for each of these traits. Greenhouse seedling emergence percentages for 12 of 18 Lewis flax accessions were not significantly different than that of ‘Appar’. Early seedling growth for six Lewis
flax accessions at three field locations was also comparable to
that of ‘Appar’. Hybridization among accessions possessing desired traits may enhance selection for high performance Lewis
flax releases.
Materials and Methods
Study Sites
Three field sites were selected to evaluate the growth
of Lewis flax in field conditions. Low-elevation sites were
selected to test drought tolerance. Brief descriptions of
the sites follow.
The Orchard site is 32 km southeast of Boise, ID, and
6.5 km south of the Orchard exit on Interstate 84. Elevation is 970 m. The soil is a deep (rooting depth greater
than 1.5 m) sandy loam with good to fair drainage and
0 to 2 percent slope. Seventy-eight percent of the 28 cm
mean annual precipitation occurs during winter and spring
(November to May). Mean annual temperature is 10.1 °C.
Principal perennial species of adjacent, somewhat intact
communities include Wyoming big sagebrush (Artemisia
tridentata ssp. wyomingensis), Sandberg bluegrass (Poa
secunda), and bottlebrush squirreltail (Elymus elymoides).
The Nephi site is 13 km southwest of Nephi, UT, on the
Utah State University Agricultural Experiment Station’s
Nephi farm. Elevation is 1,580 m. The soil is a deep loamy
clay on a 0 to 2 percent slope. Mean annual precipitation
is 34 cm, with 67 percent of the precipitation occurring
from November to May. Mean annual temperature is
9.7 °C. This typical basin big sagebrush (A. tridentata
ssp. tridentata) site has been used for testing small
grains, alfalfa (Medicago sativa), and numerous forage
grasses, forbs, and shrubs.
The Skull Valley site is 13 km north of Dugway, UT.
Elevation is 1,450 m. The soil is a deep, well-drained
sandy loam with a 0 to 5 percent slope. Mean annual precipitation is 18 cm, with 57 percent of the precipitation occurring in winter and spring. Mean annual temperature
is 11.5 °C. Few perennials remain on this site due to a
history of repeated wildfires and past overgrazing. Before
disturbance, vegetation was likely dominated by bottlebrush squirreltail, shadscale (Atriplex confertifolia), Indian ricegrass (Oryzopsis hymenoides), budsage (Artemisia spinescens), and winterfat (Ceratoides lanata).
Restoration efforts on disturbed lands in the Intermountain West require appropriate seed mixes to obtain
the desired community composition. Adapted forb species
are an important component of most of these communities, providing diversity and stability. Familiarity with
the traits of adapted forb species and their potential is essential in developing expectations for restoration efforts
(Kitchen 1994).
Few native forbs have been developed to the point that
seed is grown commercially. Cultivars exist for only a few
species, including Palmer penstemon (Penstemon palmeri),
Rocky Mountain penstemon (P. strictus), northern sweetvetch (Hedysarum boreale), and Louisiana sagewort (Artemisia ludoviciana) (McArthur 1988). ‘Appar’ was released
as a broadly adapted cultivar of Lewis flax (Linum lewisii).
Favorable traits include good seedling vigor, excellent
seed production, and a showy inflorescence (Howard and
Jorgensen 1980; Shaw and Monsen 1983). However, recent work (Pendleton and others 1993) has clearly demonstrated that ‘Appar’ belongs to the European species, perennial blue flax (L. perenne), and that it is a distinct
species from North American Lewis flax. As such, ‘Appar’
should not be used as a native.
My objective in this study was to compare the performance of populations of native Lewis flax to that of ‘Appar’
In: Roundy, Bruce A.; McArthur, E. Durant; Haley, Jennifer S.; Mann,
David K., comps. 1995. Proceedings: wildland shrub and arid land restoration symposium; 1993 October 19-21; Las Vegas, NV. Gen. Tech. Rep. INTGTR-315. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station.
Stanley G. Kitchen is a Botanist at the U.S. Department of Agriculture,
Forest Service, Intermountain Research Station, Shrub Sciences Laboratory, Provo, UT 84606.
Common Gardens
Common gardens were established with transplants in
the spring of 1989 at the Orchard and Nephi sites. Transplants were grown using seed collected from 14 native
321
populations and from ‘Appar’ seed (table 1). Replicated
plots of 24 plants each were randomly arranged within
three blocks at each site. Each plot consisted of four rows
(120 cm spacing between rows) of six plants each (60 cm
spacing within rows). Spacing between plots was 150 cm.
Individual plants were rated yearly from 1989 to 1991 at
the Orchard site and from 1989 to 1992 at the Nephi site.
All living plants were scored for vigor on a scale from 1
(low) to 5 (high). The abundance of leaves and stems and
their color, flower production, and overall succulence were
considered in determining individual plant vigor scores.
In 1990 plants at the Nephi site were also scored for rust
infection on a scale from 0 (no visible evidence of rust) to
5 (rust infection on more than 90 percent of the plant).
All plants at the Nephi site were treated with the systemic fungicide, Plantvax, in May 1990.
(maximum possible seeds per fruit is 10). After seeds
(fruits) had matured and capsules had begun opening, bulk
samples were collected from more than 20 plants of each
accession. Seed weight was determined with four replications of 100 seeds. Estimates of the total number of seeds
and the weight of seeds per plant were extrapolated from
these data.
Greenhouse Seedling Emergence
In November 1991, I evaluated seedling emergence in
controlled greenhouse conditions (25 °C during day, 15 °C
during night) for 19 Lewis flax accessions and ‘Appar’
(table 1). Fifty seeds of each accession were planted in
three replicated rows at a depth of 3.2 cm in well-drained
planter boxes. The planting medium was a loamy sand.
Row length was 70 cm; spacing between rows was 6 cm.
Boxes were watered periodically so soil moisture would
not be limiting. Emerged seedlings were counted weekly
for 42 days after planting. In addition, germination trials
were conducted on each seedlot to determine total germinable seed percentages. Four replications of 25 seeds were
placed in Petri dishes on top of two germination blotters
moistened to saturation with tap water. Petri dishes were
placed in a cardboard box enclosed in a plastic bag and
stored in the greenhouse for 21 days. Germinated seeds
were counted and removed weekly. Ungerminated seeds
were classified as dormant or dead using a simple cut test.
Emergence percentages were adjusted by dividing raw
emergence percentages by percent germinable for each
accession.
Seed Production
Seed production was determined for eight plants of 13
Lewis flax accessions (table 1) and for ‘Appar’ at the Nephi
site during 1990 and 1991. Vigorous, nonborder plants
were selected 2 weeks before flowering began. Reproductive stems were counted on each plant after flowering had
ceased. Mean numbers of flowers and fruits per stem
were estimated by counting aborted flowers and fruits on
a subsample of 20 (1990) or 10 (1991) stems from each
study plant. Seeds from 20 fruits from each plant were
harvested just before capsules were fully ripe. Seeds were
counted and divided by 200 to determine percent fruit fill
Table 1—Site information for 19 Lewis flax seed collections. ‘Appar’ perennial blue flax seeds were from a commercial
lot. Accessions were used in a combination of studies including common garden (1), seed production (2),
greenhouse emergence (3), and field seedings (4).
Collection
name
County
State
Elevation
Mean annual
precipitation
m
cm
Confusion Range
Potosi
Burr Trail
Yuba Dam
Mona
Cove Fort
Maple Grove
Lava Hot Springs
Little Antelope
Summit
Black Hills
Fort Collins
Asotin
Provo Overlook
Blue Springs Hill
Hyde Park
Richmond
Parley’s Summit
Panguitch Lake
Millard
Clark
Garfield
Juab
Juab
Millard
Millard
Bannock
White Pine
UT
NV
UT
UT
UT
UT
UT
ID
NV
1,870
1,850
2,030
1,630
1,540
1,760
2,000
1,460
2,270
22
25
25
33
34
34
36
36
36
Custer
Larimer
Asotin
Utah
Box Elder
Cache
Cache
Summit
Garfield
SD
CO
WA
UT
UT
UT
UT
UT
UT
1,340
1,760
320
1,970
1,570
1,540
1,710
2,060
2,580
36
38
38
43
43
44
47
58
58
Elk Knoll
‘Appar’
Sanpete
—
UT
—
3,160
—
71
—
322
Vegetation
type
Saltbush-grass
Pinyon-juniper
Pinyon-juniper
Sagebrush-grass
Sagebrush-grass
Sagebrush-grass
Sagebrush-grass
Sagebrush-grass
Pinyon-juniperMountain brush
Ponderosa-mahogany
Ponderosa-mahogany
Palouse grassland
Sagebrush-grass
Sagebrush-grass
Sagebrush-grass
Sagebrush-grass
Mountain brush
Ponderosabitterbrush
Alpine meadow
—
Studies
1,2,3,4
1,2,3
1,2,3,4
1,3,4
1,2,3
1,2,3
1,2,3
1,2,3,4
3
3
3
1,2,3,4
1,2,3,4
1,2,3
1,2,3
1,2,3
1,2,3
3
3
1,2,3,4
Table 2—Survival and vigor of ‘Appar’ perennial blue flax and 14
Lewis flax collections at the Orchard common garden
(planted March 1989). For all collections, 1991 survival
was less than 5 percent. Plant vigor is on a scale of
1 (low) to 5 (high). Within columns, means followed
by the same letter are not significantly different at the
P < 0.05 level (Student-Newman-Keuls multiple range
test).
Field Seedling Emergence
Small plots at the Orchard, Nephi, and Skull Valley sites
were seeded in October 1991 using seed from six Lewis
flax accessions and ‘Appar’ (table 1). Sites were fallowed
to reduce competition from weeds.
On each site, sets of four parallel furrows 5 to 10 cm deep
and 45 cm apart were made perpendicular to the prevailing winter wind direction using common farm equipment.
Seeds of each accession were planted in three 8-foot plots
(four furrows each) arranged in a randomized complete
block design. Seeding depth was 1 to 2 cm. Seeding rate
was 67 seeds per meter of row. Seedling density was determined in late spring using eight 60-cm subplots randomly located along the seeded rows of each plot. Emergence percentages were calculated from seeding rate and
seedling densities. Subjective observations for plant size,
stand survival and vigor, and flowering intensity were
made in the summer of 1993.
Transplant survival and seedling emergence percentage
data were arcsine transformed before statistical analysis.
Results of all experiments were subjected to analysis of
variance procedures appropriate to the experimental design used. Within a treatment, significant differences
among accessions were determined using the StudentNewman-Keuls (SNK) multiple range test. Regression
analysis was used to examine the relationship of mortality and vigor to rust resistance at the Nephi garden and
the relationship between emergence percentages in the
greenhouse and in the field.
Collection
Transplant survival
1989
1990
Vigor
1990
- - - - - - -Percent - - - - - ‘Appar’
Confusion Range
Potosi
Burr Trail
Yuba Dam
Mona
Cove Fort
Maple Grove
Lava Hot Springs
Asotin
Provo Overlook
Blue Springs Hill
Hyde Park
Richmond
Parley’s Summit
35a
33a
31ab
31ab
10bcde
26abc
2e
10bcde
13bcde
8cde
25abc
19abcd
21abcd
17abcd
7de
35a
31ab
28abc
26abcd
10cdef
24abcd
2f
8def
10cdef
7def
22abcde
15bcdef
9cdef
7def
2f
3.8ab
4.1a
3.4ab
3.4ab
3.0abc
3.4ab
4.0a
3.6ab
2.6abcd
2.9abcd
3.3ab
1.5cd
1.6cd
1.3d
2.0bcd
was apparent throughout the garden. Blocks of ‘Appar’
remained free of any visible evidence of infection, while
rust resistance in Lewis flax accessions varied considerably among accessions (table 3). Mortality from 1990 to
1992 was significantly correlated with mean rust index
(r2 = 0.52, d.f. = 13) even though fungicide application
Results
Common Gardens
Initial transplant survival (5 months after transplanting) at the Orchard common garden was 19.2 percent.
Survival percentages for eight Lewis flax accessions were
not significantly different than for ‘Appar’ (table 2). Mean
survival 1 year after planting was 15.7 percent. Most
mortality between years occurred among accessions collected from more mesic sites (see mean annual precipitation, table 1). At this time, survival for five Lewis flax collections was not significantly different than that of ‘Appar’.
Survival after 2 years was less than 5 percent for all accessions, including ‘Appar’ (data not shown).
Mean vigor of surviving plants at the Orchard common
garden in August 1989 ranged from 1.0 to 2.0, with no significant differences among collections (data not shown).
In 1990, mean vigor for all accessions was 2.9; mean vigor
for 12 Lewis flax accessions was not significantly different
from that for ‘Appar’ (table 2). Lower vigor tended to be
associated with collections that experienced the highest
mortality between August 1989 and April 1990. At the
Orchard site, ‘Appar’ and Confusion Range were the only
accessions that flowered to any significant extent (Kitchen,
field notes).
Transplant survival for all collections at the Nephi common garden 1 year after planting was 95.3 percent. Survival varied greatly among accessions from the summer
of 1990 to 1992 (fig. 1). Visible evidence of rust infection
was first noted in April 1990; by mid-May rust infection
Figure 1—Survival of eight representative Lewis
flax accessions and ‘Appar’ in a common garden
near Nephi, UT. Greenhouse-reared seedlings
were transplanted in April 1989. Mortality from
1990 to 1992 was significantly correlated with severity of 1990 rust infection (P < 0.05, r 2 = 0.52).
All plants were treated for rust in 1991, minimizing infection.
323
effectively controlled rust in 1991. All plants of the Confusion Range accession died by 1991. This accession
showed the greatest susceptibility to rust.
Significant differences in the vigor of surviving plants
were observed each year among accessions at the Nephi
site (table 3). In 1989, nine accessions of Lewis flax had
mean vigor values that were not significantly different
than that of ‘Appar’. In 1990, five accessions of Lewis flax
had significantly higher mean vigor values than ‘Appar’
and one had a significantly lower value. Vigor in 1991
was significantly correlated with rust infection of the pre2
vious year (r = 0.61, d.f. = 12). In 1991, mean vigor for
the Maple Grove, Asotin, Hyde Park, and Parley’s Summit accessions was not significantly different from that
of ‘Appar’. These accessions all had low rust indices.
‘Appar’ remained rust free. Vigor of surviving plants in
1992 was similar for 11 accessions, including ‘Appar’.
While several accessions had relatively high mean vigor
values in 2 or 3 of the 4 years, only Maple Grove scored
among the highest in each of the 4 years. ‘Appar’ scored
among the highest during 3 years.
set percentages in 1991 (data not shown). Two-year perplant seed production among Lewis flax accessions was
highest for the Mona, Maple Grove, Hyde Park, Cove Fort,
and Lava Hot Springs accessions.
Seedling Emergence and Growth
Seedling emergence under greenhouse conditions ranged
from 18 to 89 percent (table 5). Emergence percentages
for 12 accessions of Lewis flax were not significantly different than that of ‘Appar’. Seedling emergence in the
field varied by site. Mean emergence percentage for the
seven accessions at the Orchard site was 18 percent. There
were no significant differences among accessions. Mean
emergence at the Nephi site was 23 percent. Emergence
percentages for the Lava Hot Springs (51 percent) and
Provo Overlook (33 percent) accessions were significantly
higher than those of the other five collections, including
‘Appar’. Mean seedling emergence at the Skull Valley site
was 63 percent, significantly higher than at the other two
sites. At that site, only the Burr Trail accession had an
emergence percentage significantly lower than that of
‘Appar’. Combined field emergence percentages ranged
from 42 percent for ‘Appar’ to 22 percent for Burr Trail
and were not significantly correlated with greenhouse
emergence percentages.
No seedlings at the Orchard and Whiterocks sites survived to the summer of 1993. Observations at the Nephi
site revealed vigorous plants of each accession, all of which
flowered and produced seed.
Seed Production
Seed production for ‘Appar’ was clearly higher than for
all other accessions (table 4). However, ‘Appar’ seeds are
smaller than those of all collections of Lewis flax. The gap
in seed production between ‘Appar’ and the Lewis flax accessions is reduced when comparing grams of seeds per
plant. Though mean first-year (1990) production was 37 g
per plant for the eight most productive accessions of Lewis
flax (compared to 53 g for ‘Appar’), second year (1991) production was relatively poor or nonexistent for five of those
accessions. Data were not taken for four accessions in
1991 because the study plants died. All accessions, including ‘Appar’, experienced reduced flowering and fruit
Discussion
Factors other than species adaptability affected successful establishment of transplants. Such factors include
Table 3—Mean vigor and rust index of surviving transplants of ‘Appar’ perennial blue flax and 14 collections
of Lewis flax at the Nephi common garden. Plant vigor is on a scale from 1 (low) to 5 (high). Rust
index values were scored from 0 (no infection) to 5 (more than 90 percent of plant infected).
Within columns, means followed by the same letter are not significantly different at the P < 0.05
level (Student-Newman-Keuls multiple range test).
Collection
1989
Mean vigor
1990
1991
‘Appar’
Confusion Range
Potosi
Burr Trail
Yuba Dam
Mona
Cove Fort
Maple Grove
Lava Hot Springs
Asotin
Provo Overlook
Blue Springs Hill
Hyde Park
Richmond
Parley’s Summit
2.9a
2.9a
2.6abcd
2.7abcd
2.9a
2.4dce
2.7abc
2.9a
2.5bcde
2.2e
2.8ab
2.6abcd
2.4de
2.9a
2.1e
2.1cd
2.3b
2.2bc
2.0cd
2.1cd
2.4ab
2.0cd
2.6a
2.4ab
1.9de
2.1cd
2.0cd
2.1cd
1.9de
1.7e
324
3.9a
—
1.4c
1.6e
1.8e
2.9bcd
2.8cd
3.4abc
2.9cd
3.3abc
2.4d
3.1bc
3.5abc
2.9bcd
3.6ab
1992
2.5abc
—
2.5abc
2.2abc
2.2abc
2.5abc
2.4abc
2.6abc
2.1abc
2.9a
2.3abc
1.8bc
2.0bc
1.7c
2.2abc
Mean rust
index (1990)
0.0g
4.6a
1.0d
1.4c
1.8b
1.2c
1.0d
0.4f
0.6e
0.3f
1.7b
1.0d
0.6e
1.0d
0.1g
Table 4—Seed production per plant for ‘Appar’ perennial blue flax and 13 collections of Lewis flax at the
Nephi common garden. Within columns, means followed by the same letter are not significantly
different at the P < 0.05 level (Student-Newman-Keuls multiple range test).
Collection
Mean seeds per plant
1990
1991
Seeds per
gram
Mean grams per plant
1990
1991
- - - - - - - -g - - - - - - - - ‘Appar’
Confusion Range
Potosi
Burr Trail
Mona
Cove Fort
Maple Grove
Lava Hot Springs
Asotin
Provo Overlook
Blue Springs Hill
Hyde Park
Richmond
Parley’s Summit
34,012a
15,114b
9,548b
14,784b
14,466b
18,820b
17,323b
13,788b
7,544b
14,781b
16,865b
10,375b
10,582b
8,988b
23,126a
—
—
—
7,122b
5,626b
8,418b
5,266b
4,031b
—
8,046b
9,871b
5,939b
5,805b
641
465
343
428
360
474
452
392
513
365
481
362
381
527
53a
33abc
28bc
35abc
40ab
40ab
38ab
35abc
15c
40ab
35abc
29bc
28bc
17bc
36a
—
—
—
20b
12b
19b
13b
8b
—
17b
27ab
16b
11b
Table 5—Seedling emergence percentages of ‘Appar’ perennial blue flax and 19 Lewis
flax collections in greenhouse and field seeding trials. Within columns,
means followed by the same letter are not significantly different at the P <
0.05 level (Student-Newman-Keuls multiple range test).
Collection
Greenhouse
Seedling emergence
Field sites
Orchard
Nephi
Skull Valley
- - - - - - - - - - - - - - - - - - -Percent - - - - - - - - - - - - - - - - - - - ‘Appar’
Confusion Range
Potosi
Burr Trail
Yuba Dam
Mona
Cove Fort
Maple Grove
Lava Hot Springs
Little Antelope
Summit
Black Hills
Fort Collins
Asotin
Provo Overlook
Blue Springs Hill
Hyde Park
Richmond
Parley’s Summit
Panguitch Lake
Elk Knoll
63abcd
43bcde
89a
60abcd
41bcde
67abc
88a
68abc
58abcd
59abcd
21a
19a
—
8a
13a
—
—
—
17a
—
18c
14c
—
14c
12c
—
—
—
51a
—
88a
66ab
—
43b
59ab
—
—
—
55ab
—
19e
18e
22de
75ab
61abcd
56abcd
52abcde
67abc
38bcde
24cde
—
—
24a
24a
—
—
—
—
—
—
—
—
21c
33b
—
—
—
—
—
—
—
—
79ab
52ab
—
—
—
—
—
—
differences in the condition of seedlings when they were
transplanted, variability in transplant method among
planters, and variability in conditions (such as air temperature) during transplanting. For this reason, caution
is required in evaluating differences in 1989 survival data
among accessions at the Orchard site. Changes in survival
from 1989 to 1990 combined with 1990 vigor scores provide a truer indication of adaptation to xeric conditions,
such as those encountered there (table 2). Based on these
data, the drought tolerance of several accessions of Lewis
flax may equal that of ‘Appar’.
Interpreting data from the more mesic Nephi site requires similar caution. In general, accessions from drier
collection sites were more susceptible to rust infection and
shorter lived than those from more mesic sites. The role
of rust in among-accession differences in plant longevity
is unknown. However, rapid development and early reproductive maturity would be a great adaptive advantage
325
for accessions from sites where drought is more frequent
and more severe. Investment of resources into rust resistance or reserves necessary for long life would be less advantageous at such sites (Fenner 1985). Slower maturing
accessions (those with low 1990 vigor or lower seed production) had greater rust resistance and were longer lived.
Some of these accessions were from sites that receive up to
50 percent more annual precipitation than the Nephi site.
Because vigor is a qualitative measure subject to considerable bias, comparisons between sites or years should
not be made. For example, the overall mean vigor in 1990
was 2.9 at Orchard and 2.2 at Nephi, even though the
Nephi plants were undoubtedly larger and more productive
than those at Orchard. However, comparisons for the same
year and same site are valid because they were made by a
single team and completed within 1 day.
Vigor, as we measured it, was affected by several intrinsic factors including resource allocation patterns and resulting growth rate, resource depletion in connection with
reproduction, and susceptibility to rust. On the Orchard
and Nephi study sites, vigor for most Lewis flax accessions
was comparable to that of ‘Appar’, both when the accessions were grown as transplants and when they were
seeded, suggesting that they may have the ability to perform as well as ‘Appar’.
Accessions from collection sites receiving 34 to 44 cm
mean annual precipitation (the middle of the range for
collection sites) had the highest 2-year seed production,
although the production was considerably lower than that
of ‘Appar’ (tables 1 and 4). Further work is needed to determine how seed yield might improve if rust were controlled or other culture conditions were improved. Though
seed yields for Lewis flax accessions did not equal those
of ‘Appar’, they were probably high enough for profitable
commercial production.
Successful seedling emergence in the field is affected by
factors that vary among sites and years. None of the seven
accessions tested was superior to the rest when all three
sites are considered. In addition, there is no correlation
between the emergence means for all three study sites
and greenhouse emergence success. Greenhouse emergence from deep planting is not likely to be a useful test
or selection technique for this species.
These studies suggest that several accessions of Lewis
flax have seedling growth capabilities equal to those of
‘Appar’. However, single-year emergence percentages for
Lewis flax accessions are reduced by the portion of viable
seed that remains in the soil seed bank. In controlled germination studies, all Lewis flax accessions expressed some
combination of traits that would enable them to maintain
a seed bank (Meyer and Kitchen 1994). In this study,
‘Appar’ lacked this adaptive feature; virtually all seeds
germinated at the first occurrence of favorable temperatures. Field retrieval studies at three contrasting sites
confirmed the laboratory results. Care should be taken
not to lose the capacity for seed banking in Lewis flax releases through intentional or inadvertent selection in an
agronomic setting.
It appears that obstacles to the production and use
of Lewis flax seed are largely those associated with field
cultivation. Some accessions with otherwise favorable
traits are quite short lived and susceptible to rust. Other
accessions show relatively good rust resistance and longevity but may mature more slowly and produce less seed.
The impacts of rust control on seed production are not yet
known. There will also be additional costs associated with
chemical control of rusts.
Hybridization could be used to pool favorable traits found
in Lewis flax as a species. Hybrids that combine high levels of seed production, rust resistance, and drought tolerance are possible. We can only speculate concerning possible compromises to be encountered in such an effort.
Broadly adapted collections or hybrids that pose minimal
difficulty in seed production need to be identified. This
work represents a first step.
Acknowledgments
This research was funded in part by the U.S. Department
of the Interior, Bureau of Land Management, through Interagency Agreement ID910-IA-8. Special thanks are extended to Stephen B. Monsen, Karl Soerensen, Susan E.
Meyer, and Stephanie Carlson for many hours of careful
field and laboratory work that have made this work possible.
References
Fenner, M. 1985. Seed ecology. New York: Chapman and
Hall. 151 p.
Howard, C. G.; Jorgensen, K. R. 1980. ‘Appar’ Lewis flax
(Linum lewisii, Pursh) description, adaptation, use, culture, management, and seed production. U.S. Department of Agriculture, Soil Conservation Service, Plant
Materials Center.
Kitchen, S. G. 1994. Perennial forb life-history strategies
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