Progress 09/01/02 to 08/31/05
Outputs
This national program funded 14 research projects and 3 technology transfer projects in nine western and Midwestern states and involved 35 scientists. Of 44 wheat by jointed goatgrass hybrids tested, 84% had jointed goatgrass as the maternal parent. Cytoplasmic background of the parents did not affect the production and viability of seed from the BC1 generation of wheat by jointed goatgrass hybrids. Outcrossing of jointed goatgrass varied from 0.4 to 2.2%, whereas outcrossing of winter wheat varied from 0 to 0.3%. Outcrossing of jointed goatgrass appears to be affected more by environment than by genetic factors. Maximum distance detected of pollen movement between herbicide-resistant wheat and standard wheat was 120 feet with an average outcrossing rate of 0.2%. Mice and rabbits reduced jointed goatgrass spikelets much more than soil insects. Rodent feeding on spikelets was dependent upon the presence of vegetative cover. Deep moldboard plowing in fallow reduced
jointed goatgrass populations in the subsequent winter wheat to near zero. Winter wheat yields were higher when the stubble was burned before plowing compared to only plowing. In OK, annual moldboard plowing for 4 yr in a continuous winter wheat system reduced the jointed goatgrass populations to near zero. The use of stubble mulch systems for 4 yr led to dramatic increases in jointed goatgrass. Hybrids of crosses between winter wheat and jointed goatgrass were found in all locations, but imazamox resistant hybrids have only been found in WA. Using best management practices with herbicide-resistant wheat technology has reduced jointed goatgrass populations 85 to 95% compared to conventional winter wheat systems. Imazamox applied in the spring to jointed goatgrass in herbicide-resistant wheat has controlled the weed when conditions following treatment were warm and moist, but these treatments frequently have not been effective when conditions were dry or cool and dry after treatment.
Applying the herbicide at reduced rates in both the fall and the spring may improve control of jointed goatgrass when conditions are unfavorable. In many sites, herbicide-resistant winter wheat treated with imazamox has not out yielded adapted standard wheat varieties. Inserting one or two spring broadleaved crops into a winter wheat fallow rotation has greatly reduced jointed goatgrass populations, in some cases has increased farm profitability because of the extra crop produced every 6 yr. The national web site www.jointedgoatgrass.org continues to be a major source of worldwide information on this weed and its management. Press releases, radio interviews, newspaper articles, field tours, and producer meetings have been used to keep the agricultural community informed of the latest findings of the program. A national extension bulletin on control tactics for jointed goatgrass was published.
Impacts
Imazamox-resistant wheat has been shown to be an effective tool for the control of jointed goatgrass; however, producers must use best management practices for maximum effectiveness of this technology. Jointed goatgrass will hybridize with herbicide resistant wheat, therefore researchers and producers must be vigilant to the possibility that the resistant genes may move into the weed population. Moldboard plowing is another tool producers can use to manage jointed goatgrass. Technology transfer activities are helping wheat producers develop effective management strategies for jointed goatgrass and are keeping agricultural decision makers aware of the latest research findings.
Publications
- Cannon, J. B. 2006. Jointed goatgrass: Outcrossing, competition with winter wheat and response to timing and rate of imazamox. M.S. Thesis. Oregon State University, Corvallis.
- Hanson, B. D., C. A. Mallory-Smith, B. Shafii, D. C. Thill, and R. S. Zemetra. 2005. Pollen-mediated gene flow from blue aleurone wheat to other wheat cultivars. Crop Science 45:1610-1617.
- Hanson, B. D., C. A. Mallory-Smith, W. J. price, B. Shafii, D. C. Thill, and R. S. Zemetra. 2005. Interspecific hybridization: Potential for movement of herbicide resistance from wheat (Triticum aestivum) to jointed goatgrass (Aegilops cylindrica). Weed Technology 19:674-682.
- Rehman, Maqsood. 2005. Effect of genome location on transmission and retention of wheat (Triticum aestivum) genes in jointed goatgrass (Aegilops cylindrica). Ph. D. Thesis. University of Idaho, Moscow.
- Wicks, G., R. Anderson, T. White, P. Stahlman, and D. Morishita. 2005. Jointed Goatgrass: Control Tactics. National Jointed Goatgrass Research Program. Washington State University Extension Service. EB1935. 8 pages.
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Progress 01/01/04 to 12/31/04
Outputs
In 2004, imidazolinone-resistant wheat systems were evaluated in nine sites across the western US where jointed goatgrass is a problem. In a wheat-fallow system in CO. where the imidazolinone-resistant wheat system had been used over a four year period, goatgrass reproductive tillers were reduced to near zero. Using more diverse crop rotations only reduced goatgrass tillers 82 %. Because of drought conditions in 2003 to 2004 growing season, wheat yields in CO were low and there were no differences among the treatments. In WY in a wheat fallow system, the imidazolinone-resistant wheat system reduced goatgrass tillers by 62 % compared to using a standard wheat system. In WY, the imidazolinone-resistant wheat is not well adapted and it yielded 17 % less than the standard variety. In WA in a high rainfall zone, imazamox controlled goatgrass nearly 100 %, whereas in a low rainfall zone, imazamox reduced goatgrass tillers about 95 %. Currently available varieties of
imidazolinone-resistant wheat are not well adapted to the dry regions of WA and yielded 25 % less than standard wheat in 2004. In WA, grain dockage due to goatgrass was less than 0.002 % where imazamox had been applied compared to 0.05 to 0.27 % where imazamox had not been used. Alternating imidazolinone-resistant wheat with standard wheat every other wheat crop allowed goatgrass populations to rebound. In ID, increasing the seeding rate of conventional wheat reduced goatgrass populations 43 %, whereas using an imidazolinone-resistant wheat system reduced goatgrass by 94 %. In UT, adding safflower to a wheat-fallow rotation and using an imidazolinone-resistant wheat system reduced goatgrass populations to very low levels and improved farm profitability. In continuous winter wheat in KS, the use of imidazolinone-resistant wheat systems for three years reduced goatgrass populations to near zero. Three years of continuous standard wheat with best management practices has reduced
goatgrass populations moderately. Spikes from wheat by goatgrass hybrids were collected from fields in ID, OR, WA, and CO in 2003. Seed set in hybrids varied from 0.4 % to 5.3 %. Germination of seeds from hybrids varied between 0 and 80 %. Goatgrass was shown to be the maternal parent in 84 % of the seed from hybrids collected in ID, OR, and WA. Goatgrass had higher outcrossing rates than did winter wheat. Outcrossing rates for goatgrass varied among locations where it was grown and ranged from 0.33 % to 4.47 %. Based on tolerance of progeny to imazamox, pollen from imidazolinone-resistant wheat out-crossed to a distance of 36 m from the source. The amount of outcrossing was dependent on distance, wheat variety and wind direction.
Impacts
Imidazolinone-resistant wheat has been shown to be a useful tool for the management of jointed goatgrass, however, producers must still use best management practices with this new technology to control jointed goatgrass effectively in wheat production systems. Because currently available imidazolinone-resistant wheat varieties are not well adapted to many arid regions, they yield less that many commercial varieties. This will slow the adoption of this new technology by producers until higher better adapted imidazolinone-resistant wheat varieties are available. Because pollen from imidazolinone-resistant wheat can move the resistance genes into nearby wheat fields, users of this new technology will have to work closely with their neighbors to maintain adequate isolations distances between the fields. In UT., about 20 percent of the producers using a traditional wheat-fallow rotation has added safflower to their rotations to help manage goatgrass. This has improved
their farm profitability compared to the traditional winter wheat-fallow system.
Publications
- Anderson, R. L., D. Hanavan, and A. G. Ogg, Jr. 2004. Developing national research teams: a case study with the Jointed Goatgrass Research program. Weed Technology 18:1143-1149.
- Geier, P. W., P. W. Stahlman, A. D. White, S. D. Miller, C. M. Alford and D. J. Lyon. 2004. Imazamox for winter annual grass control in imidazolinone-resistant winter wheat. Weed Technology 18:924-930.
- Kroiss, L. J., P. Tempalli, J. L. Hansen, M. I.Vales, O Riera-Lizarazu, R. S. Zemetra and C. A. Mallory-Smith. 2004. Marker assisted retention of wheat chromatin in wheat (Triticum aestivum) by jointed goatgrass (Aegilops cylindrica) backcross derivatives. Crop Sci. 44:1429-1433.
- Rainbolt, C. R., D. C. Thill, J. P. Yenish and D. A. Ball. 2004. Herbicide-resistant grass weed development in imidazolinone-resistant wheat: weed biology and herbicide rotation. Weed Technology 18:860-868.
- Stone, A. E. and T. F. Peeper. 2004. Characterizing jointed goatgrass (Aegilops cylindrica) x winter wheat hybrids in Oklahoma. Weed Sci. 52:742-745.
- White, A. D., P. W. Stahlman, and F. E. Northam. 2004. Impact of integrated management systems on jointed goatgrass (Aegilops cylindrica) populations. Weed Sci. 52:1010-1017.
- Yenish, J. P. and F. L. Young. 2004. Winter wheat competition against jointed goatgrass (Aegilops cylindrica) as influenced by wheat plant height, seeding rate, and seed size. Weed Science 52:996-1001.
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Progress 01/01/03 to 12/31/03
Outputs
In WA under drought conditions, imidazolinone-resistant wheat was injured by imazamox applied in March and the treatment did not control jointed goatgrass effectively. In CO under drought conditions, imidazolinone-resistant wheat and conventional wheat yielded similarly and spring application of imazamox did not injure the imidazolinone-wheat. In KS in a continuous winter wheat system, imidazolinone-resistant wheat grown with best management practices and treated with imazamox had 90% less jointed goatgrass than conventional wheat grown with standard grower practices. In OK in a continuous winter wheat system, jointed goatgrass was controlled 91% when imidazolinone-resistant wheat was grown and sprayed with imazamox for two consecutive years compared to only 39% control when this system was used only in 2003. Jointed goatgrass populations were higher in winter wheat after the second annual moldboard plowing compared to populations in winter wheat after the first
moldboard plowing. In eastern WY in a wheat-fallow rotation, grain yields were 16% lower and dockage 46% higher when conventional wheat followed conventional wheat compared to when conventional wheat followed imidazolinone-resistant wheat. Standard wheat varieties are out-yielding imidazolinone-resistant wheat in most sites across the western US. The single most effective management strategy for reducing jointed goatgrass in a wheat-fallow rotation was to include a spring or summer crop. A 4-year rotation was only slightly better than a 3-year rotation for reducing jointed goatgrass densities. Other than crop rotation, single cultural practices did not consistently reduce the competitiveness of jointed goatgrass in wheat, whereas when two or more cultural practices were used in an integrated system jointed goatgrass was reduced significantly. Pollen from a point source of imidazolinone-resistant wheat moved up to 42 m as measured by outcrossing with jointed goatgrass, with some
direction effect of wind. Jointed goatgrass that germinated and emerged after mid-March at Pendleton, OR (cool, wet) or after late March at Moro, OR (warm, dry) did not produce seed before wheat harvest. Spikelet mass was not a predictor of germination potential. Low germinability of seed from spring emerging jointed goatgrass plants may be related to poor seed development rather than higher seed dormancy. Timing and frequency of fallow tillage had little impact on the density of jointed goatgrass in the subsequent winter wheat crop. Timing and duration of fall rain appeared to play a major role in determining the density and competitiveness of jointed goatgrass in winter wheat. The jointed goatgrass web site www.jointedgoatgrass.org received over 40,000 visits in 2003. In 2003, 12 press releases on jointed goatgrass were issued to agricultural magazines and newsletters.
Impacts
Because drought conditions appear to decrease the effectiveness of the imidazolinone-resistant wheat system for controlling jointed goatgrass and because imidazolinone-resistant wheat varieties generally are not as productive as conventional varieties, this technology may have limited use in arid regions. Wheat producers can reduce the severity of jointed goatgrass in wheat cropping systems by adding spring or summer crops to their rotations and by using multiple cultural control practices. Generally, timing and intensity of fallow tillage has little impact on jointed goatgrass density in subsequent wheat crops, therefore producers can reduce the amount of tillage in fallow and thus reduce soil erosion potential and production costs. The jointed goatgrass web page is serving as a major source of information on this weed.
Publications
- Wang, Z., R.S. Zemetra, J. Hansen, A. Hang, C.A. Mallory-Smith, and C. Burton. 2002. Determination of the paternity of wheat (Triticum aestivum L.) x jointed goatgrass (Aegilops cylindrica Host) BC1 plants using genomic in situ hybridization technique. Crop Sci. 42: 939-943.
- Zemetra, R.S., C.A. Mallory-Smith, J. Hansen, Z. Wang, J. Snyder, A. Hang, L. Kroiss, O. Riera-Lizarazu, and I. Vales. 2002. The evolution of a biological risk program: gene flow between wheat (Triticum aestivum L.) and jointed goatgrass (Aegilops cylindrica Host). Scientific Methods Workshop: Ecological and Agronomic Consequences of Gene Flow from Transgenic Crops to Wild Relatives. Ohio State University, Columbus, Ohio. Pgs. 178-187.
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Progress 01/01/02 to 12/31/02
Outputs
Field studies have been established in Oregon and Colorado to determine the rate of outcrossing in wheat and jointed goatgrass. A protocol has been developed and implemented for sampling large research plots in nine sites across the western US for herbicide-resistant jointed goatgrass hybrids. Best management practices compared with standard grower practices for growing imi-resistant wheat nearly double the effectiveness of imazamox at 0.027 kg/ha in suppressing jointed goatgrass tillers. Imazamox applied at 0.036 kg/ha reduced jointed goatgrass populations 90 to 99% and increased wheat yields by as much as 27%. Moldboard plowing before planting winter wheat reduced jointed goatgrass populations nearly 80% compared to stubble mulch tillage before planting. 65 BC1 plants from wheat x jointed goatgrass hybrids were screened using GISH analysis for number of C genome chromosomes. These plants had an average of 5.9 C genome chromosomes with a range of 4 to 11. Only 5 of
the 65 plants had more than 7 C genome chromosomes, indicating that only 8% of the plants were produced from a backcross with jointed goatgrass as the recurrent parent. Two national extension bulletins on jointed goatgrass were published in 2002. Over 5000 copies of the first one on ecology of jointed goatgrass have been distributed. The national web site for jointed goatgrass was completely redesigned and implemented under the unique domain name of www.jointedgoatgrass.org. Since its implementation, the site has averaged 30 users per day. Visitors from over 20 countries and five continents have accessed the new site. Five popular press articles and several press releases have been published in farm magazines and wheat grower newsletters. In May of 2002, Dr. Anthony White of Kansas State University was hired to serve as the National Jointed Goatgrass Extension Coordinator.
Impacts
By adopting the use of best management practices, wheat producers can improve the efficiency of herbicide-resistant wheat technology for controlling jointed goatgrass. Backcrossing of jointed goatgrass x wheat hybrids to jointed goatgrass is low compared to backcrossing to wheat, thus reducing the chance of gene flow from herbicide-resistant wheat to jointed goatgrass. Technology transfer activities are improving communications among scientists, extension personnel and wheat producers. Wheat producers are adopting new technologies and improved weed control practices developed by this program.
Publications
- Hanavan, D., T. White, E. Zakarison, and R. Anderson. 2002. Jointed Goatgrass: Introduction. National Jointed Goatgrass Research Program. Was. State Univ. Coop. Ext. Bull. EB 1931. 8 pages.
- Anderson, R., E. Zakarison, D. Ball, G. Wicks, D. Lyon, W. Donald, S. Miller, F. Young, and T. White. 2002. Jointed Goatgrass: Ecology. National Jointed Goatgrass Research Program. Wash. State Univ. Coop. Ext. bull. EB 1932. 7 pages.
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