COLORADO
COLORADO STATE UNIVERSITY
Department of Soil and Crop Sciences, Ft. Collins, CO 80523, USA.
S. Haley, J. Stromberger, B. Clifford, J. Butler, B. Beyer, and J. Roth.
Total winter wheat production in 2005 was estimated at 52.8 x 10^6^ bushels, a 15 % increase from the 2004 crop but still 30 % lower than the 10-year average. Average grain yield, at 24.0 bushels/acre, was 11 % lower than in 2004 and 33 % lower than the 10-year average. The area harvested for grain was estimated at 2.2 x 10^6^ acres, up from 1.7 x 10^6^ acres in 2004.
In 2004-05, the breeding program conducted field trials at six main locations in eastern Colorado (Akron, Burlington, Dailey, Julesburg, Sheridan Lake, and Walsh) in addition to the main location at the ARDEC research facility near Fort Collins. As discussed in last year's report, the Dailey and Sheridan Lake locations were added as new locations in autumn 2004 in an effort to enhance our testing capability. Overall, environmental conditions experienced at these locations can be described as follows.
Akron - excellent autumn emergence and plant stand, very lush growth in early spring, severe drought stress in early May followed by damaging high temperatures at heading. Early June rains relieved drought stress to some degree. Severe stripe rust infection were found in wetter parts of the field, low levels of leaf rust infection. Two rains at maturity delayed harvest and lowered test weights.
Burlington - excellent autumn emergence and plant stand, very lush growth in early spring, severe drought stress in early May followed by damaging high temperatures at heading. Some hail damage prior to heading. Stripe rust present in early May prevented from developing by dry and hot conditions. Trials were quite variable.
Dailey - excellent autumn emergence, stand, growth going into winter and into the early spring. Significant drought and high temperature stress was observed before and at heading. Significant autumn leaf rust infection, some overwintered into the spring though dry conditions prevented further development. Stripe rust present in early May prevented from developing by dry and hot conditions. Rains and some hail at maturity delayed harvest, trials quite variable.
Julesburg - excellent autumn emergence, fall growth. Very lush in the spring, dry conditions as at other locations, though high temperatures at heading not as damaging as elsewhere. Stripe rust infection was fairly heavy. High temperatures during grain filling.
Sheridan Lake - excellent autumn emergence, growth. Very lush in the spring. Some damage from spring freeze event in late April. Very wet May brought on significant stripe rust pressure with trace levels of leaf rust. Small plots in a much wetter part of the field than the UVPT. Some RWA found at low levels.
Walsh - excellent autumn emergence, growth. Very lush in the spring, nice dark green color indicated adequate available soil nitrogen. Good spring moisture resulted in moderate stripe rust infection by late April which became severe by early May. Some damage from spring freeze event in late April. Some RWA found, both biotype 1 and biotype 2 based on differential variety response. Russian wheat aphid, mostly biotype 1, was observed throughout the nurseries. Trace levels of leaf rust found in mid-June. Very nice trials for this location.
Fort Collins (irrigated) - excellent stands and growth in the autumn, significant autumn stripe rust infection that did not overwinter into the spring. Excellent growth and tillering occurred in the spring. Severe stripe rust infection by early June, significantly reduced yields. High temperatures throughout grain filling also was a significant factor reducing yields. Little significant lodging observed. Some severe but localized damage from RWA.
Under the direction of CSU Extension Agronomist Dr. Jerry Johnson, the CSU Variety Testing Program evaluated check cultivars and experimental lines at seven other dryland trial locations (UVPT - Bennett, Cheyenne Wells, Genoa, Lamar, Orchard, Sheridan Lake, and Yuma) and two other irrigated trial locations (IVPT - Stratton and Rocky Ford). In addition to these dryland locations, experimental lines and a reduced set of check entries also were tested at two dryland locations (Hudson and Granada) that were added in autumn 2004 in response to the continued loss of so many variety trial sites. Overall, the various UVPT trial locations experienced a variety of stresses, with spring drought stress, high temperatures at heading and during grain filling, and stripe rust being the most damaging. In spite of all of the problems, 10 out of 11 UVPT locations were successfully harvested with only Orchard being abandoned due to severe effects of the spring drought. In addition to the Fort Collins IVPT, both Stratton and Rocky Ford were both successfully harvested though yields were reduced in some of these trials due to stripe rust and high temperatures. The most significant disease or insect problem in the trials in 2005 was the severe stripe rust infection that was present at many of the locations. This infection was typically heavy at some of the irrigated locations (Fort Collins, Stratton, and Rocky Ford) and higher yielding dryland locations (such as Genoa) but was uncharacteristically heavy in southeast Colorado (including Walsh, Lamar, and Sheridan Lake) where stripe rust has been a much lesser concern the last few years. In spite of the severity of the infection observed and the high degree of apparent susceptibility of some entries, differences were noted among test entries in the capacity to fill the grain from stem reserves after stripe rust killed the leaves. Although not a problem in most trials except for perhaps the UVPT at Julesburg, WSMV was a significant problem in some areas of the state due to the mild conditions experienced in late summer and autumn 2004 that provided ideal conditions for the wheat curl mite that transmits WSMV. A side from RWA, which were observed at several locations, no other significant insect (bird cherry-oat aphid or greenbug) problems were notes.
Planted acreage estimates for the 2005 crop were as follows: Akron - 20.1 %; TAM 107 - 10.5 %; Prowers/Prowers 99 - 8.3 %; Prairie Red - 6.7 %; Trego - 6.3 %; Above - 6.1 %; Jagalene and Yumar - 4.4 %; Ankor - 4.1 %; Lamar - 3.3 %; Jagger - 2.9 %; Stanton - 1.8 %; and TAM 110 and Harry - 1.4 %.
CO00016 (CO940606/TAM107R-2) has been a top yielder in the Uniform Variety Performance Trial (UVPT) for 3 years now and will be advanced for Foundation Seed increase with the intent to release in autumn 2006. CO00016 is an early maturing line, like Prairie Red, which has been in the top group of lines in each of the last 3 years of testing (6 out of 66 in 2003, 2 out of 46 in 2004, and 3 out of 52 in 2005). Averaged across 21 dryland trial locations between 2003 and 2005, CO00016 has been the highest yielding entry in the trials, about 0.5 bu/acre higher than Bond CL, 1.7 bu/acre higher than Hatcher, 3.1 bu/acre higher than Above, 4.1 bu/acre higher than Avalanche, and 5.3 bu/acre higher than Jagalene. The principal deficiency of CO00016 is that it is quite susceptible to stripe rust, although it managed to maintain yield at some locations with severe stripe rust in 2005. Because the test weight of CO00016 is only average and its protein content is below average, CO00016 appears to have very good bread-baking quality characteristics.
With the identification of a new, virulent biotype of RWA in Colorado in 2003, and additional virulent biotypes in 2004, we have been actively involved in several different research areas to address this problem. These activities have focused on continued germ plasm screening, molecular marker identification for key resistance genes, and breeding line and population development. The following are the highlights of these activities. First, we completed the screening of 7,300 Iranian landrace selections from the NPGS for resistance to RWA biotype 2. Approximately 330 biotype 2-resistant accessions were then screened in spring 2005 for resistance to biotype 1 RWA. Approximately 155 accessions carry resistance to both biotypes; mapping populations are under development with at least five of these accessions. We are coordinating with the USDA-ARS Stillwater OK group to evaluate these lines with additional biotypes. Second, a set of five lines with biotype-2 resistance from triticale were evaluated in replicated trials at seven breeding locations. Two of these lines were very low yielding and were also shown to have problems with chromosomal stability (by Dr. Kabwe Nkongolo in Canada). Three lines showing reasonable performance and agronomic, and showing no chromosomal abnormalities, were advanced for testing to the 2006 UVPT. Third, a set of 27 line selections were made from backcross populations derived from crosses with 2414-11 and 2002 Altus-034 (a winter wheat line from Stillwater carrying the Dn7 resistance gene). These selections were planted in a single-replication observation nursery at Fort Collins in autumn 2005. Finally, many new crosses and backcross populations have been developed using resistance sources identified.
Previous research, at CSU and elsewhere, has shown that antioxidants are present in wheat bran and that varieties differ for the amount of antioxidants in the bran. Several other studies, in wheat and other plant materials, have suggested that these antioxidants contribute to reduced risk from different types of cancers. In past research, our breeding program collaborated with a scientist (who has since left CSU) on these evaluations. Unfortunately, these tests were extremely costly and laborious, thus reducing our ability to evaluate large numbers of samples for genetic experiments or selection purposes. In collaboration with Dr. Cecil Stushnoff (Horticulture and Landscape Architecture Department, CSU), one of our research associates (John Stromberger) has developed modified standard laboratory protocols for measuring antioxidant properties to allow us to conduct more high-throughput analysis. Procedures for rapid measurement of two different antioxidant properties were developed for total phenolic content and ABTS-free radical scavenging capacity. Using these assays, John evaluated a group of common varieties from several locations in eastern Colorado in 2004 to determine the extent of genetic and environmental influence on the expression of the antioxidant tests. In addition to this work, John also worked with one of our other research associates (Joshua Butler) to develop whole-grain near-infrared reflectance (NIR) calibrations that would be particularly useful for mass sample screening. We hope to complete these studies using samples collected from several locations in 2005 and will then work to validate and hopefully implement the calibrations in subsequent years.
Many hard white wheats have a predisposition to sprout in the head if wet conditions persist at harvest maturity. The severe sprouting that occurred in western KS and eastern CO in 2004 confirmed that we must pay attention to preharvest sprouting as part of our hard white wheat breeding effort. Since 2002, we have been using a technique for evaluating for preharvest sprouting tolerance of our most advanced hard white and hard red experimental lines. This technique involves sampling heads at physiological maturity in the field, drying the samples in the lab for a few days, threshing and freezing the seed samples, and then conducting controlled germination tests in a controlled-temperature incubator. In 2005, we evaluated 144 hard white samples from our breeding trials using this technique. To improve our ability to make selections based on preharvest sprouting, we modified a bread-baking proofing cabinet from our quality lab to enable sprout testing using a misting technique on intact heads. Using this procedure, we sampled about 20 heads at physiological maturity from each of 125 hard white lines that showed promise for advancement from our PYNs to the AYN. Following harvest and data analysis, we conducted the sprout tests in the mist chamber using head selections from 49 of the lines that were destined for advance. Although few of these lines showed a high level of tolerance as a group, sprout tolerant selections were identified within each of the lines, from just a few to several of the 20 head selections. These selections were advanced to the headrow reselection nursery in autumn 2005. We expect that we will continue to exploit this procedure in the future.
Several graduate student research projects are currently underway or were completed in 2004-05. Although we expect that these research projects will contribute vital information to help direct and focus breeding efforts, both the breeding project and the students benefit in many other ways though direct student involvement in the overall breeding program. Briefly, these include the following areas of research: 1) Assessment of the agronomic potential of the gibberellic acid-sensitive semidwarfing gene Rht8 (Sally Clayshulte). Sally's research demonstrated that the molecular marker that is supposedly linked to Rht8 (based largely on linkage analysis with European wheats) may not be linked with Rht8 in Great Plains germ plasm. The second year of her field evaluation of a group of recombinant inbred lines from two populations was also completed. These studies showed that an allele at the Rht8 marker locus, the WMS 261-210 allele, conferred taller plant height than the allele in most of our germ plasm (WMS261-165). Sally recently successfully defended her dissertation and has just accepted a position as a cotton breeder with Monsanto in Arizona. We thank Sally for all of her hard work and dedication over the years; she will definitely be missed. 2) Development and validation of near infrared reflectance (NIR) spectroscopy calibrations for whole-grain prediction of end-use quality characteristics (Joshua Butler). Josh began his Ph.D. dissertation studies (and his appointment as a research associate) in autumn 2004 and immediately focused on developing calibrations for test weight, kernel weight, and kernel diameter. These calibrations are extremely promising and we are nearing the point where we will use these calibrations for screening of headrow and other samples. Josh will continue to work in the coming year to refine these calibrations and also begin to develop calibrations for various measures of dough mixing strength and starch viscosity. 3) Validation of the BYDV resistance and high grain protein content traits introgressed to several elite background as part of the IFAFS molecular marker grant (Jennifer Roth, new student July 2005). Backcross populations segregating for either the BYDV resistance segment from Ag. intermedium or the high grain protein content segment from T. turgidum subsp. dicoccoides were planted in the spring at Fort Collins. Tissue samples were collected from over 2,000 plants and screened with molecular markers by the USDA-ARS Genotyping Center in Manhattan KS. Based on these assays, a subset of these lines will be increased in the greenhouse and Yuma AZ in winter 2005-06. Jennifer hopes to identify a subset of near-isogenic lines, homozygous for the presence or absence of the introgressed segment, that will be planted at several locations in fall 2006 to test for the direct and indirect effects of the introgressed segments. 4) RWA biotype-2 resistance gene mapping and gene transfer from T. turgidum subsp. dicoccoides (Ben Beyer, new student July 2005). Ben is currently developing several mapping populations developed using crosses with several RWA biotype-2 resistant Iranian landrace selections, in addition to some other sources. One of these populations will be used to identify a molecular marker linked with the resistance, which will then enable marker-assisted pyramiding of multiple RWA biotype 2 resistance genes into the same wheat variety. Ben also will be working to try to transfer RWA biotype 2 RWA resistance from a tetraploid wheat (Triticum dicoccoides) to common wheat.
The IFAFS molecular marker grant expired in 2005. In collaboration with Dr. Nora Lapitan, we have been working with funding from this grant to transfer BYDV resistance, WSMV resistance, high grain protein content, and stripe rust resistance to several released varieties (Above, Avalanche, Ankor, Stanton, and Lakin) and experimental lines (CO970547-7). We are now working to develop NILs that differ for these introgressed segments or genes that will allow us to test for their direct and indirect effects in the field in Colorado.
Over the past year, we have been working with Dr. Jorge Dubcovsky
at the University of California-Davis as the lead-PI on a continuation
and extension of this project. Together with our breeding program
and 16 other breeding programs across the U.S. Dr. Dubcovsky
recently secured a 4-year, $5 x 10^6^ grant entitled "Wheat
Applied Genomics" from the USDA-National Research Initiative-Coordinated
Agricultural Project (CAP) grant program. The grant will fund
about 75 % of a research associate, supplies, and student labor
to conduct the research. Our involvement in the grant will focus
on molecular marker mapping for various quality-related traits
in one mapping population that Dr. Pat Byrne has constructed (Platte/CO940610).
We also will collaborate with other programs in the region (Kansas
State, Nebraska, Oklahoma State, Texas A&M) in evaluating
their mapping populations in our environments, particularly focusing
on those populations that will allow identification of markers
linked to preharvest sprouting tolerance genes. As part of the
grant, we will also be increasing our use of molecular MAS through
collaboration with the USDA-ARS Genotyping Center in Manhattan
KS.