A Database for Triticeae and Avena
USDA-ARS, WHEAT GENETICS, QUALITY, PHYSIOLOGY AND DISEASE
Departments of Crop & Soil Sciences, Food Science and
Human Nutrition, and Plant Pathology, Washington State University,
Pullman, WA 99164, USA.
M.K. Walker-Simmons, L.D. Holappa, Todd Linscott, Benjamin Rangel,
John Ray, Ryan Wagner, Camille M. Steber, Janice M. Zale, Kimberly
Garland Campbell, John A. Pritchett, Lynn M. Little, R.E. Allan,
Roland F. Line, Xianming Chen, Ramon Cu, Zhixin Shi, C.F. Morris,
A.D. Bettge, H.C. Jeffers, G.E. King, B. Patterson, D.A. Engle,
M. Baldridge, B. Davis, R. Ader, T. Demeke, and M.C. Simeone.
M.K. Walker-Simmons, L.D. Holappa, Todd Linscott, Benjamin
Rangel, John Ray, and Ryan Wagner.
Cold hardiness. A crown-freezing simulation test (LT50
tests) has been developed that can differentiate cold hardy and
nonhardy Pacific Northwest wheat cultivars. Over 37,000 plants
in the club wheat breeding project have been freeze tested, and
results are being used as selection criteria to increase cold
Vrn and Fr1 genes. A project is in progress
to determine the effect of the Fr1-Vrn1 interval
and candidate genes for cold hardiness in wheat. Recombinant-inbred
lines (Norstar/Centurk) have been advanced to the F7. Potential
markers linked to the Fr1-Vrn1 interval are being
evaluated in combination with cold hardiness evaluation of the
RILs. The effect of four vernalization genes on cold hardiness
has been evaluated in NILs that differ for Vrn1, Vrn2,
Vrn3, and Vrn4 and growth habit (spring or winter).
The NILs were developed by Robert E. Allan. Spring NILs with either
Vrn2, Vrn3, or Vrn4 had a significantly greater
levels of cold hardiness compared to NILs for Vrn1.
Signal transduction and protein kinases. A wheat protein
kinase that suppresses gene expression of sprouting-damage enzymes
(alpha-amylase and protease) has been identified. This kinase
is called PKABA1 and was cloned from dormant wheat seed embryos.
The kinase transcript is ABA-responsive and expressed when wheat
seed sprouting is blocked by ABA. DNA constructs that permit continuous
expression of PKABA1, even in the absence of the natural hormone,
ABA, were developed. In collaboration with D. H.-T. Ho, Washington
University, St. Louis, MO, we demonstrated that constitutive expression
of PKABA1 drastically suppresses gene expressions of both a-amylase
and protease genes. These results indicate that PKABA1 acts as
a key intermediate in the ABA signal transduction pathway leading
to the suppression of GA-inducible gene expression in cereal aleurone
Wheat seed proteins and role in desiccation tolerance.
Heat-soluble proteins extracted from desiccation-tolerant, dormant,
wheat seeds have been demonstrated to improve survival and function
of turkey sperm during storage.
Camille M. Steber and Janice M. Zale.
Dr. Janice Zale in the laboratory of Camille Steber will be
designing an Ac-Ds transposon system for activation
tagging of wheat genes. She will transforming this system into
hexaploid wheat to provide a tool for gene cloning.
Kimberly Garland Campbell, John A. Pritchett, and Lynn M. Little.
Washington wheat growers planted 1.9 million acres of winter
wheat in 1999 (down from 2.2 million in 1998). Common white was
planted on 1,590,000 acres, and white club was planted on 142,000
acres. The rest of the winter acreage was planted to HRWW. Madsen
and Eltan were the dominant common white cultivars, and Rely had
the largest club acreage. The average yield of winter wheat in
Washington in 1999 was 58.0 bu/acre, down from 65 in 1998. Most
of the yield damage probably occurred from winter kill. Stripe
rust was mild in 1999.
The objectives of the ARS breeding and genetics program are:
To that end, in 1999, 432 crosses were made in the greenhouse,
498 F2 and F3 populations and 16,460 head rows were evaluated
visually at Pullman, 850 F4 entries were evaluated in unreplicated
yield plots, and 384 entries were evaluated in replicated yield
trials at multiple locations in Washington and Oregon. Locations
included Central Ferry, Connell, Fairfield, Hartline, Harrington,
Lind, Pomeroy, Pullman, Ritzville, St. John, and Walla Walla,
WA, plus Lexington, Hermiston, Moro, and Pendleton, OR. Separate
disease nurseries were established for foot rot, Cephalosporium
stripe, and stripe rust. The WSU winter wheat breeding program
and the WSU variety testing program assisted in the planting and
harvest of several nurseries.
Twenty-three entries were evaluated in the Western Regional
Hard Winter Wheat Nursery, 36 entries in the Western Regional
Soft Winter Wheat Nursery, and 39 in the Western Regional Spring
Wheat Nursery. The complete report for agronomic data is available
at on the web through the GrainGenes gopher at gopher://greengenes.cit.cornell.edu/11/.Performance/.westregional.
Regional selections. Five entries were sent to the 2000 regional
nurseries, three club and three common soft white wheats. 93CL0081
(Tres/VPM) and 95CL0156 (Maris Huntsman/Tres), both originally
from the Pendleton club wheat breeding program, and A96246 (Tres/Capelle
Desprez//Hyak composite/Hyak composite) are soft white clubs.
A96105, a reselection from WA7690 (VPM/M951/Yamhill/Hyslop//Hill81///Maris
Huntsman/VH745521), and A96277, a reselection from WA7810 (Stephens//Madsen/Lewjain)
are soft white common wheats. A96105 has good emergence characteristics
in both coleoptile and deep-seeding field trials (Table 1).
The ARS wheat breeding and genetics program was managed long
distance by Jim Anderson with the excellent assistance of Lynn
Little and John Pritchett. Kim Garland Campbell arrived as the
new breeder in July. Scott McDonald was hired by Oregon State
University at the Columbia Basin Research Center in Pendleton,
OR, to assist with the ARS breeding program in Oregon.
Awnless and awned of NILs of the Rht1 and Rht2
semidwarf genes affected some agronomic traits differently than
awnless and awned sibs lacking the Rht1 and Rht2
genes. The study involved NILs derived from a 'Norin 10/Brevor
14//7*Brevor' population. Brevor is an awnless non-semidwarf (rht1rht2)
SWWW that occurs in many pedigrees of U.S. and CIMMYT wheats.
'Norin 10/Brevor 14 (CI13253)' is an awned semidwarf (Rht1Rht2)
SRWW that has been used extensively in northwestern U.S. wheat
breeding programs and elsewhere.
Awnless and awned pairs of NILs with Rht1Rht2, Rht1rht2,
rht1Rht2, and rht1rht2 were grown in six tests,
and nine agronomic traits were measured. When averaged across
tests, awnless and awned, non-semidwarf (rht1rht2) NILs
differed for test weight and plant height; both traits were greater
for awnless NILs than their awned counterparts. Awned and awnless
pairs of the three semidwarf genotypes differed for two or three
traits. Awned Rht1Rht2 and rht1Rht2 NILs had heavier
test weights and kernel weights than their awnless types, but
the awnless Rht1Rht2 NIL had greater harvest index than
its awned type. The awned NIL of Rht1rht2 had greater tiller
number and percent lodging than its awnless sib.
Most semidwarf cultivars have either Rht1 or Rht2.
Regardless of awn expression, Rht1rht2 NILs had greater
test weights, plant height, and lodging percent than rht1Rht2
NILs. Conversely, both awnless and awned rht1Rht2 NILs
had greater kernels/spike and harvest index than their Rht1rht2
NILS. Awned Rht1rht2 NILs had an advantage in tiller number
over awned rht1Rht2 NILs, whereas awned rht1Rht2
NILs had heavier kernel weight than awned Rht1rht2 NILs.
For the most part, awns had either neutral or positive effects
upon semidwarf Brevor NILs, although they had either neutral or
negative effects upon non-semidwarf Brevor NILs. Awns enhanced
test weight, kernel weight, and tiller number for one or two of
the three semidwarf genotypes. Similar comparisons are planned
between awn expression and semidwarfism in several other genetic
Roland F. Line, Xianming Chen, Ramon Cu, and Zhixin Shi.
Predictive models and monitoring data were used to accurately
forecast wheat stripe rust for the 21st consecutive year and leaf
rust and stem rust for the 17th consecutive year. Stripe rust
continues to be the most important wheat disease in Washington.
Leaf rust is the second most important disease. In northwestern
Washington, the fall, winter, and spring environments were highly
favorable for establishment, survival, and increase of stripe
rust, and when not controlled, losses exceeded 20 %. In eastern
Washington and Oregon and northern Idaho, weather during the autumn
was favorable for stripe rust and leaf rust, but cold weather
in early December and dry weather in the spring were unfavorable
for increase and spread of the two rusts. Dry weather in June
and July prevented development of stem rust. Consequently, damage
from stripe rust was minimal, and damage from leaf rust and stem
rust was insignificant. The effects of the rusts on 32 winter
wheat cultivars at sites near Walla Walla and Pullman, WA, were
determined by comparing untreated plots with plots sprayed with
Folicur to control foliar diseases. The most susceptible cultivars
were slightly damaged by stripe rust. Leaf rust and stem rust
did not reduce yields in 1999.
Stripe rust, leaf rust, stem rust, and other wheat diseases
are monitored annually in the western U.S. to determine their
distribution, prevalence, and severity and to determine the vulnerability
of cultivars to local races of the pathogens. Barley stripe rust,
which was introduced into North America from Europe by way of
South America and Mexico in 1991, has spread north and west from
Texas. The disease, now indigenous in the western U.S., has significantly
impacted barley yields in Colorado, Arizona, Utah, California,
Oregon, and Washington. We have clearly determined by pathogenicity
and RAPD analysis that the wheat stripe rust pathogen is different
from the barley and grass stripe rust pathogens. The wheat stripe
rust pathogen, which attacks primarily wheat and triticale, can
attack some barley and rye cultivars, and the barley stripe rust
pathogen, which attacks primarily barley, can attack some wheat,
triticale, and rye cultivars. The bluegrass and orchard grass
pathogens are not pathogenic on wheat, barley, triticale, or rye.
At least 60 wheat stripe rust races and 50 barley stripe rust
races have been detected in North America. In 1999, the most prevalent
wheat stripe rust races were those that were virulent on Moro,
Tres, Hatton, Weston, Westbred 470, Express, and Vanna; on seedlings
of Stephens and Madsen; and on cultivars developed in regions
of the U.S. where stripe rust does not normally occur. No new
leaf rust or stem rust races were detected in the western U.S.
Powdery mildew, common bunt, flag smut, and dwarf bunt each caused
losses in the western U.S. that were less than 0.1 %.
Each year, we evaluate a new group of entries from the National
Small Grain Germplasm (NSGG) collection at Aberdeen, ID, for high-temperature,
adult-plant (HTAP) resistance to stripe rust in environmentally
different field plots at Mount Vernon and Pullman, WA, and for
seedling resistance to selected stripe rust races that include
all of the virulences that have been identified in North America.
That information is added to their database. Also, cultivars and
breeding lines developed by public and private breeders in the
western United States are evaluated annually in field plots at
multiple sites for resistance to stripe rust and other diseases.
In 1999, more than 1,200 wheat cultivars and lines from the NSGG
collection and 1,000 spring wheat and winter wheat cultivars and
advanced lines from public and private wheat were evaluated. New
lines with resistance to the rusts were identified, and cultivars
with superior resistance were released.
High-temperature, adult-plant resistance continues to be the
most effective and durable type of stripe rust resistance. Currently,
most of the major soft white winter wheat cultivars and spring
wheat cultivars grown in the western United States have HTAP resistance,
and their resistance has remained durable against all North American
races of stripe rust. In regions where stripe rust occurs, HTAP
resistance has annually prevented severe losses. Multiline club
wheat cultivars developed in the northwestern U.S. for stripe
rust resistance also have remained durable. Research on identification
of genes for stripe rust resistance continues.
We recently developed a technique for detecting molecular markers
for resistance genes that is referred to as Resistance Gene Analog
Polymorphism (RGAP). The RGAP technique is faster and more efficient,
consistent, and reliable than other techniques. The RGAP technique
was used to develop molecular markers for HTAP stripe rust resistance
and to screen NILs with specific genes for seedling resistance
to stripe rust. Molecular markers associated with HTAP resistance
genes in Stephens and resistant F7 progeny from crosses with Stephens
show possibilities as tools for identifying plants with HTAP resistance.
A cluster of three HTAP resistant genes was mapped in a linkage
group consisting of 10 RGAP markers. We identified 3, 4, 2, 1,
30, 17, 2, 6, 8, and 5 unique markers for seedling resistance
genes YrA, Yr1, Yr5, Yr7, Yr8,
Yr9, Yr10, Yr15, Yr17, and Yr18,
respectively. Of 16 markers for Yr9, four were directly
associated with and 12 were closely linked to the gene. To determine
whether the markers are present in other cultivars reported to
have Yr9, six wheat cultivars that were reported to have
Yr9 and two rye cultivars (the source of Yr9) were
tested for resistance to specific races of the stripe rust pathogen
and for presence of the markers. Five of the six wheat cultivars
and the two rye cultivars had Yr9 resistance and the associated
markers. One cultivar, Weique, did not have resistance to one
of the races and did not have the markers indicating that Weique
does not have Yr9. The location of the markers on chromosome
1BL also was confirmed. Some markers had DNA sequences similar
to disease resistance genes in rice. A probe derived from a Yr9
marker has the same kinase-gene pattern as a probe for the leaf
rust-resistance gene Lr10. This may aid in understanding
how resistance works. The results of these and other studies showed
that the RGAP technique can be used to develop specific markers
for both seedling and HTAP resistance genes, to transfer the resistance
genes to adapted wheat genotypes, and to identify the presence
of resistance genes in progeny and existing cultivars. The markers
are being used to select for a combination of Yr5, Yr8,
Yr9, and Yr15, which are the most effective genes
for seedling resistance, and to aid in crossing the selected plants
with HTAP resistant plants, such as the cultivar Stephens, in
order to combine the durable, HTAP resistance with seedling resistance.
Selecting for the markers associated with the HTAP resistance
genes should be easier and faster than selecting for HTAP resistance
by field testing advanced generations of large populations and
will be especially valuable in transferring HTAP resistance into
club wheat types.
We annually evaluate seed treatments and foliar fungicides
for control of stripe rust, leaf rust, stem rust, common bunt,
flag smut, dwarf bunt, and other diseases. In 1999, foliar fungicides
were evaluated for control of the rusts in winter and spring wheat
plots near Mt Vernon, Walla Walla, and Pullman, WA. Foliar applications
of Folicur, Tilt, Quadris, or Stratego controlled stripe rust
and protected the crop for about 1 month. Protection from the
boot to the milk stage of plant growth prevented most losses.
A computerized, expert system for predicting and managing rusts
and other diseases of wheat referred to by the acronym MoreCrop
(Managerial Options for Reasonable Economical Control of Rusts
and Other Pathogens) was developed in 1993. MoreCrop predicted
the diseases that should be problems based on geographical regions;
agronomic zones; crop managerial practices (crop rotation, tillage
methods, irrigation, planting date, and fertilizers use); cultivar
characteristics; prevailing weather; crop history; and disease
history. The program provided information, options, and suggestions
for managing the diseases and a library with information about
the diseases. Changes in hardware and software from 1993-98 provided
an opportunity to upgrade MoreCrop utilizing new computer technology.
MoreCrop version 2.0 was released in 1999. New features included
enhancement of crop managerial selections, improvement of data
management for cultivars, more flexible use of fungicides, more
diseases, and high-resolution images of the diseases. New wheat
classes and cultivars were added. A powerful database was incorporated
into the cultivar information. Data on cultivar characteristics
can be updated, and an infinite number of cultivars can be included.
Cultivars can easily be added or deleted. Use of fungicides was
made flexible to allow for updating the chemical information,
and new fungicides or fungicides with an emergency label can be
included in the disease control program. Specific rotation options
were added. Planting dates were linked to calendar dates, and
a planting depth option was added. The disease outcome was expanded
to include 30 diseases. The disease-control suggestion was expanded
so that the inference engine could search from an array of more
than a one-billion possible disease combinations. The high-resolution
images of wheat diseases were linked to the disease outcome. Also,
a system for forecasting and managing barley diseases was developed
using the concepts used to develop MoreCrop 2.0 for wheat. MoreCrop
2.0 for wheat and MoreCrop 1.0 for barley are now available on
the Internet at http://pnw-ag.wsu.edu/morecrop/.
Dr. Roland F. Line, Research Plant Pathologist, retired 31
December, 1999, after 36 years of federal service. Dr. Line served
with the Wheat Genetics Unit and the Department of Plant Pathology
at Washington State University. He worked on the control of rusts
and smuts of wheat and implemented a control program that reduced
flag smut to a minor disease and saved farmers millions of dollars.
He developed a rust monitoring program that provided early warning
to breeders and growers to enable them to take action to prevent
major losses. Since 1979, Dr. Line has used predictive models
and monitoring data to forecast wheat stripe, leaf, and stem rust,
and more recently, barley stripe rust. His computerized expert
systems for predicting and managing wheat and barley diseases
(MoreCrop for wheat and MoreCrop for barley) are available on
the internet http://pnw-ag.wsu/morecrop/ and are used by both
growers and scientists. Dr. Line will continue to provide valuable
advice on cereal disease control as an ARS collaborator.
USDA-ARS Western Wheat Quality
C.F. Morris, H.C. Jeffers, A.D. Bettge, D.A. Engle, M. Baldridge,
B. Patterson, R. Ader, and T. Demeke (ARS); G.E. King, B. Davis,
and M.C. Simeone (WSU).
We have shown recently that wheat endosperm texture (soft or
hard) results from positive genetic control by the hardness locus
(Ha) on chromosome 5DS; a complex locus coding for puroindoline-a
and puroindoline-b, collectively known as friabilin. In the wild
type, both puroindolines are normal (functional), resulting in
soft wheat. To produce hard wheat, one or the other puroindoline
is nonfunctional. We now have characterized seven unique hardness
alleles in hexaploid wheats. A set of NILs differing in grain
hardness has been released and is being registered.
We have developed laboratory scale alkaline noodle tests to
assist in screening potential cultivars for suitability in Asian
noodle applications. The test uses 100-g flour and an alkaline
salt solution to produce noodle sheets that are analyzed for color;
especially the L* value (of the L*a*b* scale) at 0 and 24 hr after
noodle production. The results provide information about the degree
of discoloration in noodles brought about by PPO.
Additionally, a buffered L-DOPA test for rapid, small-scale
assessment of PPO in single kernels has been developed. This test
affords rapid (about 1 hr), nondestructive assessment of PPO content
at early generations of wheat breeding programs and will assist
breeders in producing low PPO wheat for use in Asian style noodles.
Research on isolating PPO clones and mapping LDOPA activity are
Noting that two current cultivars, Daws and Centennial, have
bimodal distribution of PPO content, we have used the L-DOPA PPO
assay to physically separate low from high PPO kernels and are
in the process of increasing the low PPO kernels as potential
re-released improved cultivars.
We have developed an RIL population from Kanto 107 and Bai
Huo. The material is being used in research to compare the contribution
of waxy alleles to starch properties. Confirmed waxy, D-null Bai
Huo germ plasm was registered and released. One hard and one soft
full-waxy germ plasm were released and are being registered.
Our cultivar development program screened over 8,000 experimental
breeding lines for milling and baking quality and provided the
results to wheat breeders for use in their programs.
The WWQL-led PNW Wheat Quality Council held a forum to discuss
potential new cultivars and the comments and concerns about wheat
quality issues. The forum in Honolulu, HI, was attended by people
representing growers, researchers, breeders, marketers, and end-users.
Morten Lillemo, from the Agricultural University of Norway
completed a 9-month study leave to conduct research on puroindoline
effects on hardness in Northern European wheats. Dr. Marco Simeone
of the University of Tuscany, Viterbo, Italy, joined the WWQL
as a postdoctoral research associate to study the relationships
between puroindoline gene sequence and function in grain hardness.
Prof. Hak-Gil Chang, Department of Food and Bioengineering, Kyungwon
University, Sungnam, South Korea, has joined the lab to spend
a 1-year sabbatical working on grain quality research.
WASHINGTON STATE UNIVERSITY
Spring Wheat Breeding and Genetics Program, Department of
Crop and Soil Sciences, 201 Johnson Hall, Pullman, WA 99164-6420,
K. Kidwell, G. Shelton, V. DeMacon, B. Barrett, J. Smith, and
The overall goal of wheat breeding efforts at WSU is to enhance
the economic and environmental health of wheat production in the
Pacific Northwest by releasing genetically superior varieties
for commercial production. Traditional breeding methods and molecular
genetic technology are combined to improve the efficiency and
effectiveness of variety improvement efforts. Progress has been
made towards developing PCR-based tags for genes associated with
RWA resistance, spring growth habit (Vrn-B1), and a chromosomal
segment from T. turgidum subsp. dicoccoides that
is associated with a 1-2 % increase in grain protein content.
Research efforts have been initiated to identify potential gene
donors for Rhizoctonia resistance among Ae. tauschii accessions
and other wild relatives of wheat.
K. Kidwell, G. Shelton, and V. DeMacon.
Over 500 crosses were made in 1999, and more than 30,000 experimental
breeding lines and released varieties of soft white, hard red,
hard white, or spring club wheats were evaluated in field trials
at 1 to 15 locations in eastern Washington, depending on seed
availability. The F1 seed from 508 lines was increased to generate
segregating progenies for use in conventional breeding strategies,
MAS, and gene-linkage analyses. Approximately 288 F2 and 368 F3
families were advanced to the next generation, and 3,243 entries
among 29,170 F4 and 1,010 F5 head rows were selected, based on
stripe rust reaction and phenotype, for early generation end-use
quality assessment. Following phenotypic selection, grain from
selected head rows (2,834) was evaluated visually for plumpness.
Selections with sound grain were separated by market class, then
entries from each market class were subjected to a specific assessment
strategies depending on end-use goals. Grain protein content and
grain hardness were determined on whole grain flour using the
Technicon (NIR). Microsedimentation (microsed) and flour-swelling
volume (FSV) were used to assess protein and starch quality, respectively,
of selected lines. Polyphenol oxidase levels also were determined
for soft white and hard white material to assess noodle color
potential before selecting lines to advance to 2000 field trials.
Grain samples from 812 experimental lines with superior agronomic
performance were sent to the USDA-ARS Western Wheat Quality Laboratory
(Pullman, WA) for milling and baking evaluations.
Hessian fly resistance. Six novel (H5, H11,
H13, H22, H25, and H26) Hessian fly-resistance
genes have been transferred into adapted spring wheat germ plasms
for all four market classes of spring wheat grown in the region.
Following field evaluation of 127 resistant lines in single-plot
yield trials in Pullman in 1999, 76 (20 soft and 56 hard) high-yielding
lines were submitted to the WWQL for end-use quality assessment.
Entries with superior end-use quality will be evaluated in replicated,
multilocation yield trials in 2000.
Russian wheat aphid. Five unique RWA-resistance genes
have been incorporated into elite spring wheat germ plasms from
the PNW. Over 600 resistant head rows were evaluated in the field
in Pullman in 1999. Based on phenotypic selection for plant type,
maturity, and stripe rust reaction, and 115 were selected for
advancement to single-plot yield trials in the year 2000.
Variety releases. The soft white experimental line WA7850,
tentatively named Zak, will be released in 2000 as the
Wawawai and/or Alpowa replacement. Zak has excellent grain yield
potential and outstanding end-use quality properties. Zak is stripe
rust resistant and has intermediate resistance to the Hessian
fly. Foundation seed of Zak will be produced in 2000. The PVP
status of Zak is pending.
The experimental line WA7824, tentatively named Tara,
will be released in 2000 as the replacement for Westbred 926,
the primary HRSW in commercial production in the PNW. Tara is
a high-yielding, Hessian fly-resistant line with exceptional gluten
strength. This variety is well adapted to production in direct
seed systems. Breeder's seed of Tara will be produced in 2000.
The PVP status of Tara is pending.
B. Barrett and K. Kidwell.
A rapid, plant-advancement protocol was developed by which
plants are forced to go from seed to seed within a 10- to 12-week
period in the greenhouse. This allows us to advance progeny of
a single cross through four to five generations per year, which
greatly accelerates the breeding process. A wheat microsatellite
marker associated with a chromosomal segment that confers a 1-2
% grain protein content (GPC) increase in two donor lines, GluPro
and ND683, was identified, then a strategy was developed to rapidly
move this segment into adapted germ plasm through marker-assisted
backcross breeding. Initial crosses between the protein segment
donor parents and the adapted hard red varieties Scarlet and Tara
were made in 1998. The goal is to recover lines nearly identical
to Scarlet and Tara with the addition of the increased GPC segment
from the donor parents. BC4 lines containing 97 % of the genes
from the WSU lines and 3 % of the genes from the donor parents,
including the high protein segment, have been developed using
this strategy. Initial field evaluations of these materials will
begin in 2000.
J. Smith and K. Kidwell.
Rhizoctonia root rot is a prominent disease of spring cereal
grains in direct seed management systems in the PNW. To date,
genetic resistance to this disease has not been identified in
cultivated wheat or barley. The objectives of this study are to
1) determine whether current spring wheat and spring barley cultivars
vary in their levels of susceptibility to R. solani AG-8
and 2) identify potential gene donors among wild relatives of
wheat for use in cultivar improvement. Fifteen spring wheat cultivars,
12 spring barley cultivars, 10 D. villosum accessions,
D. villosum/durum amphiploids, Agropyron amphiploids,
and D. villosum addition lines were evaluated for disease
reaction to R. solani AG-8 in growth chamber analyses.
Preliminary screening results indicated that, although variation
in disease reaction was detected, all current spring wheat and
spring barley varieties are susceptible to Rhizoctonia root rot.
However, D. villosum appears to be a viable source of genetic
resistance to R. solani AG-8.
M. Bayram, B. Barrett, and K. Kidwell.
Wheat microsatellite and AFLP markers linked within 1.1-20.6
cM of the spring growth-habit gene Vrn-B1 were identified in reciprocal
mapping populations generated by crossing NILs with the recessive
winter (vrn-B1) and dominant spring (Vrn-B1) growth
habit alleles. This demonstrates the effectiveness of using these
types of populations to identify DNA markers closely associated
with genes of interest. These DNA tags will be used in MAS strategies
to combine Vrn-B1 with other spring growth habit genes
into single varieties in an attempt to enhance grain yield potential.