A Database for Triticeae and Avena
USDA-ARS, WHEAT GENETICS, QUALITY, PHYSIOLOGY AND DISEASE
RESEARCH UNIT AND WASHINGTON STATE UNIVERSITY
Departments of Crop & Soil Sciences, Food Science and
Human Nutrition, and Plant Pathology, Washington State University,
Pullman, WA 99164, USA.
Xianming Chen, David A. Wood, Mary K. Moore, Paul Ling, and
Rust monitoring, loss assessment, and race identification.
Wheat stripe rust, leaf rust, and stem rust were monitored throughout
the PNW using trap plots and field surveys in 2002. Stripe rust
was predicted accurately for the PNW using monitoring data and
predictive models based on susceptibility of wheat cultivars and
environmental factors such as temperature and precipitation. Through
collaborators in other states, wheat stripe rust was monitored
throughout the United States. Wheat stripe rust occurred from
California and the PNW to Georgia and Virginia and from Louisiana
and Texas to Wisconsin and Ohio. Severe yield losses caused by
stripe rust occurred in Arkansas, California, and the PNW. In
2002, stripe rust epidemics caused wheat yield losses about 8
x 106 bushels plus multi-million dollars on fungicide application
in the United States.
In the PNW, 2002 was the most severe year of wheat stripe rust
probably for the last 10 years. The stripe rust epidemics were
more severe in the higher rainfall regions in eastern Washington
and northern Idaho, mainly on spring wheat. Severe stripe rust
occurred in nurseries of common and durum wheat in Oregon. In
Washington state, the 2002 stripe rust epidemic affected about
440,000 acres (70 %) of spring wheat and 45,000 acres (2.5 %)
of winter wheat. Acreage affected by stripe rust was about 20
% of the total wheat acreage. Over 170, 000 acres of spring wheat
were sprayed with fungicides at a cost of over $2.5 x 106 USD.
Without the fungicide control, stripe rust could have caused 20-25
% (about 5.7-7.1 x 106 bushels) yield losses. The fungicide applications
saved $17 to 30 x 10^6^ USD for Washington wheat growers. The
severe stripe rust epidemics on spring wheat were due to the favorable
weather conditions, new races of the pathogen, and widely grown
susceptible cultivars. The 2001-02 winter temperatures were higher
and the 2002 spring temperatures were lower than normal, favoring
stripe rust development. Precipitation was frequent in May and
June and provided adequate moisture for stripe rust infection
over a long period. A group of new races and races that were detected
in 2000-01 in California and east of the Rocky Mountains attacked
Zak and some other spring wheat cultivars that were grown over
150,000 acres in eastern Washington and northern Idaho. The durable,
high-temperature, adult-plant resistance that is in most winter
wheat cultivars and some spring wheat cultivars grown prevented
wheat crops from epidemics that could have caused much worse damages.
The multiline cultivar Rely, with various seedling-resistance
genes, has been grown for more than 10 years and was the number
one club wheat cultivar from 1994-2000 and the second most-grown
club wheat cultivar in 2002, still showed excellent resistance
to stripe rust.
Through collaborators, a total of 314 samples of wheat stripe
rust were obtained from 16 states (AL, AR, CA, CO, GA, ID, IN,
KS, LA, MO, OH, OR, TX, VA, WA, and WI) in 2002. More than 20
races of P. striiformis f. sp. tritici were detected.
Races PST-78 (virulent on Lemhi, Heines VII, Lee, Fielder, Express,
Yr8, Yr9, Clement, and Compair), PST-80 (the same
virulences of PST-78 plus virulence on Produra), and two new races
(the same virulences of PST-78 or PST-80 plus virulence on Stephens)
were predominant throughout the United States except northwestern
Washington. This group of races caused the epidemics in Arkansas,
California, and Washington.
In 2002, wheat leaf rust was light in the PNW, probably because
of the wide application of fungicides to control stripe rust that
also controls leaf rust and stem rust. Only trace stem rust was
found in commercial fields. Yield losses due to leaf rust and
stem rust were minimal. Leaf rust and stem rust samples were sent
to the USDA-ARS Cereal Disease Laboratory, University of Minnesota,
for race identification . Two races, MBGJ (virulent on Lr1,
Lr3a, Lr10, Lr11, and Lr14a) and MBBS
(virulent on Lr1, Lr3a, LrB, Lr10,
and Lr14a), of P. triticina were detected in Washington
state. These races were different from MDBJ (virulence on Lr1,
Lr3a, Lr10, Lr14a, and Lr24), the
only race detected in 2001. Virulences of the 2002 Washington
races were similar to those of the most predominant race MBDS
(virulent on Lr1, Lr3a, Lr10, Lr14a,
Lr17, and LrB).
Evaluation of wheat germ plasm and breeding lines for resistance
to stripe rust. In 2002, more than 8,000 entries of wheat
germ plasm and breeding lines from the NSGC and wheat breeders
were evaluated for stripe rust resistance in fields under natural
infections and in the greenhouse with selected races to cover
all possible virulences. The evaluation data were provided to
the NSGC for the germ plasm database and to breeders for developing
and releasing resistant cultivars. Resistant germ plasm was selected
for characterizing resistance, determining genetics of resistance,
and mapping genes conferring resistance.
Determining the genetics of stripe rust resistance and developing
wheat germ plasm with superior resistance to stripe rust.
To determine genetics of stripe rust resistance in wheat cultivars
Alpowa, Express, ID377s. and Zak, crosses and backcrosses of these
cultivars with susceptible cultivars Avocet Susceptible (AVS)
were made in the field and greenhouse. Seed of F1, F2, and BC1
were obtained for developing RILs for genetic studies and molecular-marker
development. Advanced backcrosses will be made for developing
NILs for determining the virulences of the pathogen, study host-pathogen
interactions, and to improve genetic resistance. To fix the problem
of susceptibility in Zak to stripe rust and improve the level
of resistance in Alpowa, both Zak and Alpowa were crossed with
the Yr5, Yr15, and Yr18 NILs that were developed in the Plant
Breeding Institute, University of Sydney, Australia. F1 seed were
obtained for all these crosses and also obtained from four-way
crosses (Zak/Yr5//Zak/Yr15 and Alopwa/Yr5//Alpowa/Yr15). Molecular
markers we developed for Yr5 and Yr15 will be used to screen backcross
progeny and to accelerate the introgression of the effective resistance
genes into the Zak and Alpowa backgrounds. We also made crosses
between the Yr18 NIL with AVS for developing molecular markers
for the durable APR gene and use the markers to incorporate Yr18
into Zak and Alpowa, which would bring durable resistance into
Zak and improve the level of durable resistance in Alpowa.
To determine wheat resistance to the barley stripe rust pathogen,
crosses were made between Lemhi and PI 478214. Lemhi is susceptible
to all races except PST-21 of P. striifromis f. sp. tritici
but resistant to all races of P. striifromis f. sp. hordei.
PI 478214, an Ethiopian spring wheat genotype, is susceptible
to both P. striiformis f. sp. tritici and f. sp.
hordei. Preliminary results indicate that Lemhi has a single
dominant gene for resistance to the barley stripe rust pathogen.
Similarly, the barley cultivar Steptoe, which is susceptible to
all races of P. striifromis f. sp. hordei, has a
single dominant gene conferring resistance to P. striiformis
f. sp. tritici. Currently, F2, F3, and BC1 progeny are
being tested with appropriate and inappropriate races to determine
the relationship between the Lemhi gene for resistance to P.
striiformis f. sp. hordei and its Yr21 for resistance
to PST-21 of P. striiformis f. sp. tritici. Molecular
markers are being developed to map these genes.
Developing molecular markers for stripe rust-resistance
genes and constructing BAC libraries for cloning resistance genes.
To incorporate Yr5 and Yr15 resistance against
all races of P. striiformis f. sp. tritici identified
in the U.S. into wheat cultivars, the resistance-gene analog polymorphism
(RGAP) technique was used to identify markers for the genes. The
Yr5 and Yr15 NILs were backcrossed to AVS to develop
mapping populations. We constructed a high-density map for Yr5
with 16 RGAP markers using 202 BC7:F3 lines. Six of the markers
were completely associated with the Yr5 locus. Sequence
analyses revealed that two codominant and Yr5-cosegregating
markers, Xwgp-17 and Xwgp-18, had 98 % homology
with each other and had significant homology with many plant resistance
genes, resistance gene analogs, and expressed sequence tags. We
developed STS markers with primers based on the sequences of Xwgp-17
and Xwgp-18. The STS markers worked well in some, but not
all, F1 progeny of crosses and cultivars. Through collaborating
with Jorge Dubcovsky at U.C. Davis, we further developed CAPS
markers for Yr5 by digesting the STS fragments with the DpnII
enzyme. The CAPS markers worked well with F1 progeny of all tested
crosses and cultivars. For Yr15, we constructed a high-density
map with 11 RGAP markers using 196 BC7:F4 lines, one marker completely
co-segregated with and the others were linked to Yr15.
We used five of the markers to determine presence or absence of
Yr15 in breeding lines. Both marker and disease tests clearly
indicated Yr15 in one of 13 lines tested. The markers are
used to combine Yr5 and Yr15 into elite-breeding
Toward cloning Yr5 and other wheat genes for resistance
to stripe rust, we have been constructing a BAC library using
the genomic DNA from the Yr5 NIL digested with HindIII.
The library now contains 200,000 clones with an average size between
120 and 130 kb, equivalent of 2X hexaploid wheat genome. The Yr5-cosegregating
RGAP markers will be used to screen the library to identify clones
containing the Yr5 gene.
Evaluating fungicides for integrated control of stripe rust.
Foliar fungicides were evaluated for controlling stripe rust in
spring wheat plots near Pullman, WA. Susceptible Fielder and moderately
susceptible Vanna spring wheat cultivars were planted on 30 April,
2002. Seven fungicide treatments were conducted on 25 June at
early boot stage. Plots that were not sprayed were used as untreated
check. A randomized-block design was used with four replications
for each treatment. Data on stripe rust severity (percent foliage
with stripe rust) were recorded on 19 July at milk stage and on
26 July at soft-dough stage. Yields were determined from plots
harvested in September. All the fungicide treatments effectively
reduced stripe rust severity. Folicur, Quadris, and A 13705 SC
200 applied at 2.6 and 1.96 fl oz significantly increased grain
yield compared to the untreated checks on Fielder. Only A13705
SC 200 applied at 1.96 fl oz significantly increased grain yield
To determine the yield gain in cultivars with various levels
of resistance/susceptibility from fungicide application to control
stripe rust, 24 cultivars were used in the winter wheat experiment
and 16 cultivars were used in the spring wheat experiment using
a randomized split-plot design with four replications. The fungicide
Quadris was sprayed at the rate of 6.2 oz/acre when the winter
crops were in late heading stage and the spring crops were in
late boot to early heading stage and highly susceptible cultivars
had 10 % stripe rust. Stripe rust occurred naturally in the nonfungicide-treated
plots. Rust severities were recorded 33 and 25 days after the
fungicide spray in the winter wheat and spring fields, respectively.
Stripe rust severities developed in the winter wheat field to
80-85 %, 50-60 %, 10-30 %, and 0-9 % on the susceptible, moderately
susceptible, moderately resistant, and resistant cultivars, respectively;
and in the spring wheat field to 8595 %, 7080 %, 38-45
%, and 0-5 % on the susceptible, moderately susceptible, moderately
resistant, and resistant cultivars, respectively. The fungicide
application increased yield by over 45 %, 20-40 %, 10-18 %, and
0-9% for the susceptible, moderately susceptible, moderately resistant,
and resistant winter wheat cultivars, respectively; and by 40-83
%, 25-39 %, 10-20 %, and 4-8 % for the susceptible, moderately
susceptible, moderately resistant, and resistant spring wheat
cultivars, respectively. These data can be used to make appropriate
recommendations for fungicide application according to cultivars.
Several sets of NILs have been developed, described and deposited
into the USDA-ARS National Plant Germplasm System. Genetic traits
for which they differ and their PI numbers are provided. To date
these sets have not been registered with Crop Science Society
NILs differing for heading date. Paha is a soft white winter
club wheat cultivar having a midseason heading date and excellent
club wheat quality. Paha was grown in the U.S. PNW in the 1970s.
Nord Desprez NILs differing for reduced height. Nord Desprez
is an old soft red French winter wheat cultivar that has been
used as a parent in several U.S. PNW breeding programs. 'Norin
10/Brevor 14' contributed RhtB1b and RhtD1b genes.
Soft white winter NILs differing for reduced height and awn
expression. 'Norin 10/Brevor 14' and 'CI13253/7*Brevor'. CI13253
has genes RhtB1b RhtD1b for reduced height and a
gene for awnedness. Brevor has RhtB1a BhtD1a for
normal plant height (103 cm) and a gene for awnlessness. Brevor
was an important SWWW grown in the U.S. PNW during 1952-64.
Tom Thumb reduced-height NILs. Growth habit, market class,
plant height, and plant height genes of the recurrent parents
of these NILs are Brevor (SWWW, 106 cm, RhtB1a RhtD1a),
Moro (soft white winter club, 110 cm, RhtB1a RhtD1a),
Olympia (SWWW, 140 cm, RhtB1a RhtD1a), Stephens
(SWWW, 82 cm, RhtB1b RhtD1a), Daws (SWWW, 87 cm,
RhtB1a RhtD1b), and Tres (soft white winter club,
92 cm, RhtB1a RhtD1b). 'Tom Thumb/7*Burt' contributed
the RhtB1c gene.
Spring versus winter growth habit NILs. The recurrent parent
Marfed is a SWSW that was widely grown in the U.S. PNW during
1956-76. Coldhardiness of these NILs was reported by Storlie et
al. Crop Sci 38:483-488, 1998.
Kimberly Garland Campbell, Robert E. Allan, Todd Linscott,
Kay Walker-Simmons, and Eric Weir.
Our objective was to compare the response to artificial freezing
for near-isogenic wheat genotypes differing for vernalization
(Vrn) loci. We regularly conduct artificial freezing tests in
growth chambers in the WSU Plant Growth Center that are able to
cool to -25 C. The basic test is as described in Storlie (Storlie
et al. 1998) and the result is an LT50 value (or temperature at
which 50 % of the plants are survive).
R.E. Allan has developed two sets of NILs for each of four
Vrn genes in a winter wheat background. Each set used the
Triple Dirk NILs developed by Pugsley (Zeven et al. 1986) as Vrn-gene
donors (see Table 1). Two SWWW cultivars were used as recurrent
parents: Daws (Peterson et al. 1977) with good winter hardiness
and Wanser with less winter hardiness. In our tests, the LT50
of Daws has consistently been 3 C less (colder) than that of Wanser.
Table 1. LT50 values for near-isogenic lines
of Daws differing for Vrn loci. Values followed by the
same letter are not significantly different based on Fisher's
protected LSD test.
Each Triple Dirk NIL initially was backcrossed twice to each
recurrent parent with selection for the presence of the Vrn
allele. Six more backcrosses were made using the recurrent parent
as a male and a spring-habit progeny from the previous generation
as a female (for example: Daws*2/Triple DirkD)*6//Daws). Within
the progeny of each of four or five BC7 families/cross, a winter
and a spring sibling was identified. Each sibling was selfed and
its growth habit was checked in both a greenhouse and field environment
during 1999 and 2000. Spring-habit NILs were retained only if
they were homozygous for spring habit. Thus, each NIL set is comprised
of each of the four Vrn loci as 4-5 families possess ing
both a winter and spring sib for a total of 36-40 NILs/recurrent
parent. Theoretically, Triple Dirk alleles make up 0.37 % of the
genome of each NIL.
The LT50 values of the Daws NILs were determined. All
Vrn loci resulted in LT50 values similar to the recurrent
parent except for Vrn-A1 (Table 1) (spring habit). The
presence of the Vrn-A1 allele caused a major reduction
in cold hardiness, supporting previous research that noted the
major effects of chromosome 5AL on cold hardiness. Because of
the effects of the Vrn-A1 allele, the mean LT50 values
for spring-habit NILs were higher than the mean for winter-habit
NIls. There was no change in LT50 values associated with the vrn-a1
allele (winter habit) in the Daws NILs. The reduction in cold
hardiness associated with Vrn-A1 is either extremely closely
linked to Vrn-A1 or an effect of Vrn-A1 itself.
There were no differences in LT50 values among any of the other
Vrn alleles. This indicates that we can develop winter
hardy spring habit wheat cultivars by using Vrn-B1 or Vrn-D1.
Those facultative-habit cultivars are useful in dry-cropping situations
when planting is depending upon moisture. These results also indicate
that the Vrn loci and loci closely linked to them are not
likely to be important sources of improved winter hardiness in
Daniel Z. Skinner and Kwang-Hyun Baek.
The expression levels of antioxidant enzyme genes were monitored
in winter and spring wheat NILs during cold acclimation. The 442
(winter wheat) and 443 (spring wheat) NILs developed by Dr. R.E.
Allen differed only in the Vrn1A-Fr1 region of chromosome
5A. Total RNA was extracted from wheat grown at a constant 20
C for 2 weeks, then at 2 C for 1, 2, or 4 weeks. Using gene-specific
primers, quantitative RT-PCR was used to measure the levels of
RNA transcripts from 11 genes. The antioxidant genes monitored
were mitochondrial MnSOD, chloroplastic Cu, ZnSOD, FeSOD,
CAT, ascorbate peroxidase (APX), gutathione reductase (GR), glutathione
peroxidase (GP), mono-dehydroascorbate reductase (MDHAR), and
dehydroascorbate reductase (DHAR). The expression levels of glyceraldehyde-3-phosphate
dehydrogenase (GAPDH) and b-actin also were monitored during cold
acclimation to evaluate these genes as possible constant-expression
standards for wheat cold-acclimation studies.
The expression levels of the antioxidant enzyme genes were
up-regulated (MnSOD, MDHAR, AP, DHAR, GP, and GR), down-regulated
(CAT), or maintained constant expression (FeSOD and Cu, ZnSOD).
The genes that were up-regulated reached their highest expression
levels after 2 weeks, then declined or maintained constant expression
to 4 weeks. The Vrn1A-Fr1 region seemed to play a role
in regulating the expression level of some of the antioxidant
enzyme genes in low temperature. NIL 442 has significantly higher
expression levels of MnSOD, CAT, and APX than NIL 443 after 4
weeks of cold exposure. GAPDH and b-actin had significantly higher
expression levels during cold acclimation, therefore, those enzymes
cannot be used as standards in these studies.
These results suggested that antioxidant enzyme genes may play
a role in cold response of wheat plants. The response appears
to manifest to its highest level within the first week of exposure
to cold, and appears to be influenced by the alleles present at
the Vrn1A-Fr1 region.
USDA-ARS WESTERN WHEAT QUALITY
LABORATORY [p. 234-235]
E-202 Food Science & Human Nutrition Facility East, Washington
State University, Pullman, WA 99164, USA.
Craig F. Morris, A.D. Bettge, D.A. Engle, M.L. Baldridge, R.L.
Engle, G.E. King, G.L. Jacobson, A.N. Masa, I. Eujayl, E.P. Fuerst,
K.R. Gedye, C.C. Burke, J.F.Connett, W.J Kelley, M.J. Freston,
P.K. Boyer, L. Nguyen, E.E. Galli, S.M. Finnie, C.A. Oliver, S.M.
Leach, and Y. Haruta.
The mission of the lab is two-fold: conduct milling, baking
and end-use quality evaluations on wheat breeding lines and conduct
research on wheat grain quality and utilization. The lab continues
to move into web-based information transfer and has added extensive
enhancements to our web site, http://www.wsu.edu/~wwql/php/index.php.
To provide greater access to our research, we developed a database
of wheat cultivars relating kernel hardness and puroindoline allele.
We are in the process of placing our research publications on
our web site.
We are serving as curator of the Grain Hardness, Puroindoline
and GSP-1 gene sections of the Catalogue of Gene Symbols in Wheat.
Several new alleles have been documented in Ae. tauschii and other
C.F. Morris and D.A. Engle lead the PNW Wheat Quality Council,
a consortium of collaborators who evaluate the quality of new
cultivars and advanced-breeding lines.
A.D. Bettge currently serves as chairman of the AACC Soft Wheat
and Flour Technical Committee. New methodology for the analysis
of end-use characteristics of wheat is studied by this committee
for inclusion in the AACC's Approved Methods manual. Recent methods
that have been studied collaboratively and approved include solvent-retention
capacity, which estimates a number of end-use quality factors
such as protein quality, starch damage, and pentosan content,
and flour-swelling volume, which measures starch swelling and
the impact of granule-bound, starch-synthase allelic state. Currently,
the committee is studying an L-DOPA substrate-based method for
estimation of polyphenol oxidase content of wheat, a contributor
to Asian noodle discoloration.
Post-doctoral research associates include A.N. Masa, Eujayl,
E.P. Fuerst, K.R. Gedye, and C.C. Burke. Y. Haruta is a visitor
from a Japanese milling company.
WASHINGTON STATE UNIVERSITY
Departments of Crop and Soil Sciences, Food Science and Human
Nutrition, and Plant Pathology, Pullman, WA 99164-6420, U.S.A.
K. Kidwell, G. Shelton, V. DeMacon, M. McClendon, J. Baley,
and R. Higgonbotham.
Overview. The overall goal of wheat breeding efforts
at WSU is to enhance the economic and environmental health of
wheat production in the PNW by releasing genetically superior
cultivars for commercial production. Traditional breeding methods
and molecular genetic technology are combined to reduce production
risks associated with abiotic and biotic stresses by incorporating
genetic insurance into adpated, elite varieties.
Seven hundred crosses were made in 2002, and 27,334 breeding
lines were evaluated in field trials at 1 to 16 locations in Washington
state. Grain samples from 522 breeding lines with superior agronomic
performance were sent to the USDA-ARS Western Wheat Quality Laboratory
for end-use quality assessment. Two cultivars, Macon (HWSW) and
Eden (spring club) were approved for release. Macon is a Hessian
fly-resistant cultivar with exceptional bread-baking and noodle-making
properties. Eden has outstanding grain yield potential, traditional
club quality, and excellent stripe rust resistance. Research efforts
were initiated to 1) incorporate a high protein region and stripe
rust resistance genes into adapted spring wheat cultivars using
MAS, 2) assess broadly adapted wheat germ plasm for resistance
to Phythium, and 3) assess soilborne disease pressure in glyphosate
tolerant wheat production.
New cultivar prereleases and releases. Scarlet,
a 1998 WSU release, was the primary HRWW in commercial production
in Washington State in 2002. Scarlet was released for the semiarid
production region as a replacement for Butte 86 and Kulm, however,
the cultivar has broad adaptation and acreage has extended well
beyond the targeted region into the intermediate-rainfall zone.
Although Scarlet has performed well in the semiarid region of
Washington state, it has relatively low test weight when stressed
and is not excessively tall cultivar. Scarlet also is moderately
susceptible to the race of stripe rust that prevailed in the region
in 2002 and is susceptible to the Hessian fly. Originally, our
goal was to develop a cultivar specifically for the semiarid region
with the yield potential of Scarlet but that is taller, and has
higher test weight, higher grain-protein content, and improved
bread-baking quality compared to those of Scarlet. The agronomic
performance and phenotypic characteristics of WA007859 align nicely
with these requirements. WA007859 also is resistant to current
races of stripe rust in the region, and is resistant to local
Hessian fly biotypes, which improves its suitability for direct
seed production in the low- and intermediate-rainfall zones. In
7 out of 8 site-years in cultivar-testing trials at Lind and Horse
Heaven, WA, grain yields of Scarlet were statistically similar
to those of WA007859. Based on 23 site years of data from the
low-rainfall zone, WA007859 has a 0.6 lb/bu test weight advantage
over Scarlet, and the grain protein content of WA007859 is 0.4
% higher than that of Scarlet. The bread-baking quality of WA007859
also is superior to that of Scarlet. WA007859, which will be named
Hollis, was approved for cultivar release. Foundation seed of
this cultivar will be produced in 2003.
Nearly 100,000 acres of the SWSW Zak were grown in Washington
State in 2002, its first year in commercial production. Based
on its high yield potential, superior end-use quality and Hessian
fly resistance, Zak was projected to be an ideal replacement for
Wawawai and Alpowa in the high-rainfall zone. In previous years,
Zak demonstrated resistance to stripe rust races present in the
region; however, Zak, along with many other SWSWs in commercial
production, was highly susceptible to the race that prevailed
in the region in 2002. Costs associated with spraying fungicide
to control stripe rust reduce the profit potential of this cultivar
and increase the risk of environmental contamination. The highest
priority for the spring wheat-breeding program is to release a
stripe rust-resistant replacement for Zak with equivalent or superior
grain-yield potential and end-use quality characteristics. We
also would like to replace a substantial proportion of the Alpowa
acreage in the high-rainfall zone with a cultivar that has improved
end-use quality, Hessian fly resistance, and better emergence
under direct-seed production conditions. WA007921 has excellent
potential as the Zak and Alpowa replacement in areas receiving
more that 15 inches of average annual precipitation. WA007921
was rated as having moderate resistance to stripe rust in 2002
and is partially resistant (65 %) to the Hessian fly. The grain-yield
potential of WA007921 was equal to or better than those of Zak,
Alpowa, and Wawawai in a majority of the dryland field trials
conducted from 1999 to 2002. The end-use quality of WA007921 is
equivalent or superior to that of Zak, and this cultivar is a
dramatic end-use quality improvement over Alpowa. WA007921 was
approved for prerelease and Breeder seed of this cultivar will
be produced in 2003.
In 2002, 16,000 acres of SWSW were grown in Washington state.
A majority of this acreage was sown to Idaho 377s, which was licensed
by the University of Idaho to a grower coöperative. Although
ADM Spokane successfully produced Idaho 377s locally on contract
in 2002, many growers are interested in obtaining hard white wheat
cultivars through public release channels to reduce seed costs
and to create flexibility in production and marketing strategies.
Although Idaho 377s has excellent yield potential and superior
noodle color, it does not mill particularly well and has suboptimal
bread-making quality. In 2002, we released Macon, a dual-purpose,
HWSW suitable for noodle and bread making with acceptable but
not exceptional agronomic performance. Macon is resistant to local
biotypes of the Hessian fly; however, it is moderately susceptible
to the new race of stripe rust that prevailed in the region in
2002. Our goal is to release a public cultivar to replace Idaho
377s and to identify a stripe rust resistance compliment for Macon
that has superior grain-yield potential, a broad adaptation range,
and dual-purpose quality. WA007931 has outstanding grain-yield
potential that equals or exceeds those of Idaho 377s and Macon
across production zones. WA007931 has far better bread-making
quality than that of Idaho 377s, and it has excellent noodle color.
However, the bread-making quality of Macon is superior to that
of WA007931. WA007931 would be an outstanding compliment to Macon
in that it is much taller and has higher test weight, making it
more suitable for production in the semiarid and intermediate-rainfall
zones. WA007931 also is moderately resistant to stripe rust and
is partially resistant to the Hessian fly. WA007931 is a partial
waxy type, which might make it suitable for producing different
types of noodles than which Macon is suited. Releasing cultivars
with complimentary quality attributes will broaden the market
range for PNW hard white wheat.
M. McClendon and K. Kidwell.
High protein gene introgression. Increasing grain protein content
by applying high rates of N fertilizer can be effective, but it
is inefficient. Instead of relying solely on fertility management
to increase grain-protein content of HRS, avenues to genetically
enhance this trait through traditional breeding methods are now
available. A promising genetic source of high grain-protein content
(HGPC) was detected in a wild relative of wheat. Researchers speculate
that a grain-protein content increase of 1-2 % can be expected
if the HGPC region is introgressed into a bread wheat cultivar,
and this protein content increase is expected to occur without
additional nitrogen fertilizer requirements. The objective of
this project is to increase GPC of the hard red varieties Scarlet
and Tara 2002 by introgressing the region into these lines through
marker-assisted backcross breeding. BC5F3 and BC6F2 lines, containing
> 99 % of the genes from the WSU lines and < 1 % of the
genes from the donor parents, including the high protein segment,
were developed using this strategy, and this material was evaluated
in the field in 2002.
Over 100 isolines (BC5F3), containing 99 % of the genes from
the Scarlet or Tara 2002 with 1 % of the genes from Glupro, with
or without the HGPC segment, were evaluated in a nonreplicated
field trial at WSU's Spillman Farm in 2002. A soft white fertility
regime (2.5 lb N/expected bu) was used to maximize fertility response
differences among isolines. This trial was heavily infested with
stripe rust, and susceptible lines were eliminated from consideration.
Even though nonreplicated data from a single site-year must be
interpreted with extreme caution, several isolines appear to have
excellent potential as high protein replacements for Scarlet and
Tara 2002. Replicated field trials will be initiated in 2003 to
assess the impact of incorporating the HGPC region into these
Stripe rust resistance. Zak, a Hessian fly-resistant SWSW was
slated to replace Wawawai, Penawawa, and perhaps some Alpowa acreage
in the high-rainfall region based on its excellent yield potential
and superior end-use quality. Prior to 2002, Zak had demonstrated
excellent resistance to stripe rust races prevalent in the field.
In commercial production in 2002, Zak showed high levels of susceptibility
to stripe rust, indicating that recently developed races have
circumvented the resistance in Zak. Incorporating new rust resistance
genes into Zak is a high priority since this cultivar would have
been the premiere SWSW in commercial production in the region
if its stripe rust resistance had held. Stripe rust resistance
genes Yr5 and Yr15 are effective against all races
identified so far in the U.S., and tightly linked molecular markers
for these genes have been developed. The primary goal of this
project is to introgress Yr5 and Yr15 into Zak as
quickly and efficiently as possible by utilizing the recurrent
enriched backcrossing breeding scheme.
R. Higginbotham, T. Paulitz, and K. Kidwell.
Pythium root rot, a fungal pathogen of wheat, causes yield
losses in virtually every field in Washington. Even though Pythium
damage is well-documented, limited information about which isolates
are most responsible for disease occurrence is available. Nineteen
Pythium isolates were tested for pathogenicity on two spring wheat
cultivars. A complete random design was used to evaluate cultivars
in inoculated and non-inoculated treatments in a growth chamber
maintained at 16°C with ambient humidity. Plant height, length
of the first true leaf, number of seminal roots, and crown root
number were recorded, and roots were digitally scanned into computer
files that were analyzed using WinRhizo software. Preliminary
results indicated all of the Pythium isolates caused a significant
reduction in the number of root tips (P < 0.0001), root surface
area (P = 0.0001) and root length (P = 0.0001), whereas average
root diameter increased (P = 0.001) due to a reduction in the
number of fine secondary roots. Virulence level varied among species,
and isolates with the highest pathogenicity levels will be used
to assay a broad range of germ plasm for tolerance/resistance.
J. Baley, T. Paulitz, and K. Kidwell.
Glyphosate tolerant wheat will permit 'in crop' weed control
while maintaining the intrinsic environmental and economic benefits
associated with no-till crop production. However, potential yield
gains may be lost because of increased activity of soilborne pathogen
on dying weeds within a glyphosate tolerant wheat crop. The objective
of this study is to proactively determine the risks of incorporating
glyphosate tolerant wheat into no-till production systems. Bobwhite
and Westbred 926 NILs with and without glyphosate tolerance were
evaluated under direct-seed conditions in three agroclimatic zones
in eastern Washington. A mixture of spring barley and sterilized
oat seed inoculated with Rhizcotonia solani/oryzae or Gaeumannomyces
graminis var. tritici (GGT) were direct seeded into the field
plots prior to planting the NILs to simulate greenbridge volunteer.
A no greenbridge control also was included. NILs from three treatments
(RoundUp, Buctril/Harmony Extra, and a no-spray, hand-weeded control)
were evaluated for disease severity and agronomic performance.
Roots were digitally scanned and analyzed using WinRhizo software
to assess morphological changes within treatments. All NILs were
evaluated with the Buctril/Harmony Extra and no-spray treatments,
but only the glyphosate tolerant varieties were treated with glyphosate.
Regardless of disease treatment or location, glyphosate treated
Roundup Ready® (RR) spring wheat, produced significantly (P
= 0.001) more grain than NILs treated with Buctril/Harmony Extra
or the no-spray control, suggesting that greenbridge transmission
of Rhizoctonia and GGT due to Roundup application may not occur
at high enough levels to suppress yields of RR cultivars. Rhizcotonia
and GGT naturally prevail in areas receiving low and high levels
of precipitation, respectively. In trials planted in the low and
high rainfall zones, grain yields of NILs treated with Buctril/Harmony
Extra were significantly (P = 0.05) lower than NILs treated with
Roundup or the no-spray control. High levels of yield depression
with this treatment was unexpected since wheat producers in the
PNW typically use Buctril/Harmony Extra for broadleaf weed control.
However, Harmony Extra is a sulfonylurea herbicide, which is a
group of herbicides that have been shown to increase the incidence
of R. solani and GGT in wheat, which may have impacted these results.
An interesting herbicide-pathogen interaction was noted in a trial
that was heavily infested with stripe rust. Bobwhite NILs that
had not been treated with Roundup had a more severe incidence
of stripe rust than Roundup-treated NILs. Bobwhite NILs sprayed
with Buctril/Harmony Extra or in the no spray control displayed
severe stripe rust-susceptibility symptoms and matured 2-3 weeks
earlier than NILs treated with Roundup. Buctril/Harmony Extra
treated RR Bobwhite produced significantly (P = 0.01) less grain,
than the RR Bobwhite treated with Roundup, regardless of root
disease treatment. Visual differences in stripe rust severity
were not apparent until 21 days after herbicide application. These
results suggest that glyphosate within a RR-wheat plant may remain
active for extended time periods, thereby hindering the colonization
of leaf tissue by foliar pathogens. If true, residual in-plant
glyphosate activity also may be responsible for increased grain
yields detected for Roundup treated RR NILs across locations,
regardless of disease treatment. Additional field trials, along
with concurrent growth chamber analysis of root structure, defense
enzymes and products, will be conducted to elucidate the effects
of Roundup application on the transmission of soilborne pathogens
to herbicide-resistant wheat.