OREGON
OREGON STATE UNIVERSITY
Crop and Soil Science Department, Corvallis, OR 97331-3002 USA.
Warren E. Kronstad, Project leader.
Progress.
The cereal variety prerelease committee has approved the release of five
new wheat varieties including: 1) two SWWWs, 2) a HWWW and a HWSW, and 3)
a club wheat selection. These selections have evolved through selection
and testing over a wide range of environmental conditions. A shuttle breeding
approach is employed for the winter wheats involving the Chambers' site
in the Willamette Valley, Sherman Branch Experiment Station at Moro, and
the Rugg's location near Adams. In addition, such breeding lines are exposed
to specific stresses or management systems, e.g., the Stockman site north
of Helix for winter hardiness, the Kaseberg farm near Wasco for dryland,
and the Anderson farm near Ione for an irrigated environment. The spring
trials are conducted at the Rugg site, and the club wheats are evaluated
at Moro and at the Columbia Basin Research Center. In 1996, the club wheats
were evaluated at the Rugg's site, as well.
Soft white winter selections.
Two SWWW selections that have been identified for possible release are OR880172
and OR898120. Both selections have complex pedigrees representing 'winter
x spring' crosses. In addition to broad adaptation, they both were developed
for specific objectives. OR880172 is particularly well adapted to western
Oregon owing to its resistance to Septoria leaf blotch. OR880172 has been
competitive in yield only at the Chambers' site. In contrast, OR898120 is
better adapted to the conditions observed in eastern Oregon and is superior
in yield to the current commercial cultivars. In addition to its resistance
to most foliar diseases, it is resistant to Columbia Basin foot rot. Another
positive aspect of this selection is the quality of the straw, which is
much easier to handle following harvest than the stubble of Madsen.
Hard white selections.
OR850513 represents the first HWWW selection from the program to be considered for release. Several high yielding HWWW selections have been either dropped or recycled through the program because of deficiency in specific quality attributes. OR850513 has yielded similarly to Stephens at both Rugg's and Moro, is superior at the Chambers' location, and also appears to have acceptable resistance to foliar diseases.
The HWSW selection OR4870453 is superior agronomically to both the check varieties in yield and disease reaction to the two rusts. This selection has received very high marks by different Asian noodle evaluation teams participating in the Quality Laboratory at the Wheat Marketing Center in Portland.
Club wheat.
Prior to the transfer of the club wheat breeding program to the ARS program
at Washington State University, the most promising club wheat selection
developed at the Columbia Basin Research Center was identified for release.
This selection, 92CL0054, is comparable to Rohde when grown at Pendleton,
Moro, and the Rugg's sites for agronomic, disease, and milling and baking
properties. In yield, it has been equal, inferior, and superior to Rohde,
depending on the year and location. 92CL0054 is resistant to Columbia Basin
strawbreaker foot rot, a major problem in Rohde. When compared to Tres and
Paha, 92CL0054 is slightly lower in some milling scores, but superior in
cookie diameter and cake volume.
Future prospects - soft white winter wheat.
The resurgence of Stephens, in terms of grower preference, raises a question
if another such cultivar is under development. For a cultivar to still prevail
after 20 years of commercial production is quite amazing in the history
of wheat breeding. Several observations can be made regarding this situation.
First, unlike Stephens, several of the selections appear to do better at
specific locations even between north central Oregon locations. For Corvallis
and perhaps the other sites as well, the genetic potential of the selections
are influenced by the major disease complex present, i.e., Septoria at Corvallis
and root rot complexes in eastern Oregon.
When heading date and plant height are considered, the selections tend
to be later and taller than Stephens. For a number of disease complexes,
such traits tend to provide an escape mechanism. However, they all appear
to have genetic resistance to the major diseases including Columbia Basin
strawbreaker foot rot. Without exception, these selections represent a significant
enhancement of SWWW quality in both milling and baking properties. This
is unique, because most often the breeder's dilemma is that yield and quality
are related inversely.
Screening for disease resistance.
A major problem in breeding for Columbia Basin strawbreaker foot rot resistance
has been overcome by using an association of an isozyme locus (gene) and
the VPM/Moissan 421 foot rot resistance. The system was developed by Dr.
McMillin at Georgia State University and adopted by Bob Allan, a former
ARS scientist, who is now on the staff at WSU. Dr. Allan and Ms. Little
have shared their methodology with us, and Ms. Kate Chochia of our group
has successfully employed the procedure in identifying resistant selections.
The advanced selections all appear to have high levels of resistance to
this disease.
Christina Cowger, a graduate student working with Chris Mundt, has identified
a seedling screening procedure using chlorophyll content to identify resistance
to cephalosporium stripe. Again, like Columbia Basin strawbreaker foot rot,
previous field evaluations have not proven successful, because of the nature
of these pathogens. Thus, two major limitations to developing resistant
cultivars to these difficult diseases have been overcome through cooperative
efforts between research groups in the Pacific Northwest.
Another difficult disease problem, especially for early fall plantings,
is BYDV. The genetic factors for resistance to this disease from Dr. Phil
Larkin in Australia have been backcrossed into advanced soft white parents.
The fact that the resistance came from a grass and was transferred to wheat,
this apparently has resulted in some instability in maintaining the resistance.
Fortunately, some lines appear to be stable and have a high level of resistance.
Herbicide tolerance.
The development of imidozolinone-tolerant wheat remains as a high priority.
Both backcrossing and employing the wheat x corn double haploid approaches
are being used to transfer this gene into adapted cultivars. When successful,
it will be possible to use the herbicide AC299263 to control jointed goatgrass,
cheat grass, wild oats, and foxtails. One problem that will be answered
with this harvest is if the herbicide-tolerant gene is associated with red
seed coat color. There is some evidence that this may be true, and as a
consequence, large segregated populations are being grown to break up such
a relationship. This program is being conducted in coöperation with
Dan Ball at the Columbia Basin Research Center and Carol Mallory-Smith in
the Crop and Soil Science Department.
Future plans.
A much greater effort will be focused on further improving the end-use quality
of soft and hard white wheats. Without question, quality will be the number
one factor in an increasingly competitive marketplace. The quality laboratory
at the Wheat Marketing Center in Portland and the USDAARS Wheat Quality
Laboratory at Pullman, Washington, are making significant impacts on the
development of superior quality cultivars. This is true, both in evaluating
genetic materials and in providing opportunities for our graduate students
to conduct quality-related research in their laboratories.
Studies are continuing on the use of HMW- and LMW-glutenin subunits as an example of molecular marker selection to identify and follow genetic factors for superior quality. This then allows for an evaluation of both protein quantity and quality.
One current investigation is addressing the question of variety x environment x management interactions that contribute to variation in quality attributes. To ensure that a consistent supply of wheat is available to meet buyer specifications, such information is critical. To evaluate such interactions, three diverse experimental locations are being employed with different management practices. Both SWWW and HWWW cultivars and selections are being evaluated as to their quality stability when subjected to different growing environments.
Further research is being done on drought tolerance. A study has just been completed on the role of soluble carbohydrates and their relation to drought tolerance. This research has provided an insight into the potential measures of drought tolerance, but like all good research, this study also has provided more opportunities to be investigated.
For dryland areas, stand establishment work will continue. A semidwarf line with a longer coleoptile is being used and should help to avoid problems with depth seeding and crusting. Efforts also will continue to capture the excellent emergence properties of Moro for the common white wheats.
The breeding program will focus continue on soft and hard white wheats with emphasis on winter types. The encouraging noodle quality observed in several of the spring lines will be incorporated into the winter material. Agronomic information on fertilizer response as it relates to protein will be important for both soft and hard white wheats.
Publications.
Kronstad WE and Ammar K. 1997. Gluten protein polymeric composition and allelic variation as related to bread making quality in durum wheat (Triticum turgidum L. var. durum).
Kronstad WE and Larson M. 1997. Genotype-environment interaction and
phenotypic stability of selected winter wheats (Triticum aestivum L.
em Thell).
Kronstad WE and Rosa Filho O. 1997. Effect of the six glutenin loci on selected
bread quality traits in wheat.
Kronstad WE and Weight C. 1997. Possible associations between three procedures to measure noodle starch quality in winter wheat (Triticum asetivum L.).