Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-04T19:49:54.625Z Has data issue: false hasContentIssue false

Review of Glyphosate and ALS-Inhibiting Herbicide Crop Resistance and Resistant Weed Management

Published online by Cambridge University Press:  20 January 2017

Jerry M. Green*
Affiliation:
DuPont Crop Protection, Stine-Haskell Research Center, Building 210, Newark, DE 19714

Abstract

Weed management is a perennial challenge for growers, and continual innovation is essential to maintain the effectiveness of management technologies. The first generation of herbicide-resistant crops revolutionized weed control. However, weeds are adapting to crop systems that rely on a single mode of herbicide action. Crops with resistance to multiple modes of herbicide action could help maintain weed management. GAT/HRA is a new multiple herbicide–resistance technology for corn, soybean, and other crops. GAT/HRA combines metabolic glyphosate inactivation with an acetolactate synthase (ALS) enzyme that is insensitive to ALS-inhibiting herbicides. The mechanism to inactivate glyphosate is the glyphosate N-acetyltransferase enzyme, which transforms glyphosate into a nonphytotoxic metabolite. The gat gene is derived from a naturally occurring soil bacterium and optimized by repetitive gene shuffling and screening. The resistance mechanism to ALS-inhibiting herbicides is a double-mutant, highly resistant ALS (HRA) that is insensitive to all five classes of ALS herbicides. GAT/HRA crops will maintain natural tolerance to selective herbicides and thus provide more weed management options for growers to help deter weed spectrum shifts and delay the evolution of herbicide-resistant weeds.

Type
Extension/Outreach
Copyright
Copyright © Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

Alcocer-Ruthling, M., Thill, D. C., and Shafii, B. 1992. Differential competitiveness of sulfonylurea resistant and susceptible prickly lettuce (Lactuca serriola). Weed Technol. 6:303309.Google Scholar
Anonymous, , 1994. Canadian Food Inspection Agency Regulatory Directive Dir. 94-11: The Biology of Zea mays L. (Corn/Maize). Canadian Food Inspection Agency. http://www.inspection.gc.ca/english/plaveg/bio/dir/dir9411e.shtml. Accessed: September 23, 2005.Google Scholar
Anonymous, , 2002. Managing Glyphosate-Resistant Weeds—An Investment in Land Value. Syngenta Crop Protection. http://www.syngentacropprotection-us.com/Resources/Prod/Touchdown/Land_Values.pdf. Accessed: October 31, 2005.Google Scholar
Anonymous, , 2006. Practical Approaches to Managing Weeds. Monsanto Company. http://www.weedresistancemanagement.com/. Accessed: January 6, 2006.Google Scholar
Arias, R. S., Netherland, M. D., Atul, P., and Dayan, F. D. 2005. Biology and molecular evolution of resistance to phytoene desaturase inhibitors in Hydrilla verticillata and its potential use of produce herbicide-resistant crops. Pest Manag. Sci. 61:258268.Google Scholar
Andreasen, C., Stryhn, H., and Streibig, J. C. 1996. Decline of the flora on Danish arable fields. J. Appl. Ecol. 33:619626.Google Scholar
Baerson, S. R., Rodriquez, D. J., Tran, M., Feng, Y., Biest, N. A., and Dill, G. M. 2002. Glyphosate-resistant goosegrass. Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase. Plant Physiol. 129:12651275.Google Scholar
Baucom, R. S. and Mauricio, R. 2004. Fitness costs and benefits of novel herbicide tolerance in a noxious weed. Proc. Natl. Acad. Sci. USA 101:1338613390.Google Scholar
Bedbrook, J. R., Chaleff, R. S., Falco, S. C., Mazur, B. J., Somerville, C. R., and Yadev, N. S. 1995. Nucleic acid fragment encoding herbicide resistant plant acetolactate synthase. U. S. Patent 5,378,824.Google Scholar
Benbrook, C. M. 2003. Impacts of genetically engineered crops on pesticide use in the United States: The first eight years. Sandpoint, ID Northwest Science and Environmental Policy Center, AgBioTech InfoNet, Technical Paper No. 6.Google Scholar
Bernasconi, P., Woodworth, A. R., Rosen, B. A., Subramanian, M. V., and Siehl, D. L. 1995. A naturally occurring point mutation confers broad range of tolerance to herbicides that target acetolactate synthase. J. Biol. Chem. 270:1738117385.Google Scholar
Bisht, N. C., Burma, P. K., and Pental, D. 2004. Development of 2,4-D-resistant transgenics in Indian oilseed mustard (Brassica juncea). Curr. Sci. 87:367370.Google Scholar
Boerboom, C. M., Wyse, D. L., and Somers, D. A. 1990. Mechanism of glyphosate tolerance in birdsfoot trefoil (Lotus corniculatus). Weed Sci. 38:463467.Google Scholar
Bradley, K. W., Li, J., and Monnig, N. H. 2006. Greenhouse investigations of suspected glyphosate-resistant common waterhemp populations from Missouri. Weed Sci. Soc. Am. Abstr. 46:206.Google Scholar
Bradshaw, L. D., Padgette, S. R., Kimbal, S. L., and Wells, B. H. 1997. Perspectives on glyphosate resistance. Weed Technol. 11:189198.Google Scholar
Brainard, D. C. and Bellinder, R. R. 2004. Assessing variability in fecundity of Amaranthus powelli using a simulation model. Weed Res. 44:203217.Google Scholar
Buchanan-Wollaston, V., Naser, A., and Cannon, F. C. 1992. A plant selectable marker gene based on the detoxification of the herbicide dalapon. Plant Cell Rep. 11:627631.Google Scholar
Buhler, D. D. 2002. Challenges and opportunities for integrated weed management. Weed Sci. 50:273280.Google Scholar
Cajacob, C. A., Feng, P. C., Heck, G. R., Murtaza, F. A., Sammons, R. D., and Padgett, S. R. 2004. Engineering resistance to herbicides. in Christou, P. and Klee, H., eds. Handbook of Biotechnology. Chichester, UK J. Wiley. 353372.Google Scholar
Castle, L. A., Siehl, D. L., Gorton, R., Ratten, P. A., Chen, Y. H., Bertain, S., Cho, H. J., Duck, N., Wong, J., Liu, D., and Lassner, M. W. 2004. Discovery and directed evolution of a glyphosate tolerance gene. Science 304:11511154.CrossRefGoogle ScholarPubMed
Cavan, G. and Moss, S. R. 2001. Managing the risks of herbicide resistance in wild oat. Weed Sci. 49:236240.Google Scholar
Chaleff, R. S. and Ray, T. B. 1984. Herbicide-resistant mutants from tobacco cell-cultures. Science 223:11481151.Google Scholar
Christopher, J. T., Powles, S. B., Liljegren, D. R., and Holtum, J. A. M. 1992. Resistance to acetolactate synthase inhibitors in annual ryegrass (Lolium rigidum) involves at least two mechanisms. Plant Physiol. 100:19091913.Google Scholar
Coble, H. D. 1994. Future directions and needs for weed science research. Weed Technol. 8:410412.Google Scholar
Coble, H. D. and Warren, L. S. 1997. Weed control investigations in corn, cotton, crop rotations, soybean, small grain. Annu. Rep. Dep. Crop Sci. N.C. State Univ. 28:103113.Google Scholar
Culpepper, A. S. 2006. Glyphosate-induced weed shifts. Weed Technol. 20:277281.Google Scholar
Deen, W., Hamill, A., Shropshire, C., Soltani, N., and Sikkema, P. H. 2006. Control of volunteer glyphosate-resistant corn (Zea mays) in glyphosate-resistant soybean (Glycine max). Weed Technol. 20:261266.Google Scholar
DeGennaro, F. P. and Weller, S. C. 1984. Differential sensitivity of field bindweed (Convolvulus arvensis) biotypes to glyphosate. Weed Sci. 32:472476.Google Scholar
Didierjean, L., Gondet, L., Perkins, R., Lau, S. M. C., Schaller, H., O'Keefe, D. P., and Werck-Reichhart, D. 2002. Engineering herbicide metabolism in tobacco and Arabidopsis with CYP76B1, a cytochrome P450 enzyme from Jerusalem artichoke. Plant Physiol. 130:179189.Google Scholar
Diggle, A. J., Neve, P. B., and Smith, E. P. 2003. Herbicides used in combination can reduce the probability of herbicide resistance in finite weed populations. Weed Res. 43:371382.Google Scholar
Dill, G. M. 2005. Glyphosate-resistant crops: history, status and future. Pest Manag. Sci. 61:219224.Google Scholar
Doyle, P. and Stypa, M. 2004. Reduced herbicide rates—a Canadian perspective. Weed Technol. 18:11571165.Google Scholar
Drake, J. W., Charlesworth, B., Charlesworth, D., and Crow, J. F. 1998. Rates of spontaneous mutation. Genetics 148:16671686.Google Scholar
Duke, S. O. 2005. Taking stock of herbicide-resistant crops ten years after introduction. Pest Manag. Sci. 61:211218.Google Scholar
Duke, S. O. and Cerdeira, A. L. 2005. Potential environmental impacts of herbicide-resistant crops. in Collection of Biosafety Reviews. Vol. 2. Trieste, Italy International Centre for Genetic Engineering and Biotechnology. 66143.Google Scholar
Dyer, W. E. 1994. Resistance to glyphosate. in Powles, S.B. and Holtum, J.A.M., eds. Herbicide Resistance in Plants. Boca Raton, FL Lewis. 229241.Google Scholar
Elmore, R. W., Roeth, F. W., Nelson, L. A., Shapiro, C. A., Klein, R. N., Knezevic, S. Z., and Martin, A. R. 2001. Glyphosate-resistant soybean cultivar yields compared with sister lines. Agron. J. 93:408412.Google Scholar
Feng, P. C. C., Tran, M., Chiu, T., Sammons, R., Heck, G., and Cajacob, C. 2004. Investigations into glyphosate-resistant horseweed (Conyza canadensis): retention, uptake, translocation and metabolism. Weed Sci. 52:498505.Google Scholar
Forcella, F., Wilson, R. G., Renner, K. A., Dekker, J., Harvey, R. G., Alm, D. A., Buhler, D. D., and Cardina, J. 1992. Weed seedbanks of the U.S. cornbelt: magnitude, variation, emergence, and application. Weed Sci. 40:636644.Google Scholar
Franz, J. E., Mao, M. K., and Sikorski, J. A. 1996. Glyphosate: A Unique Global Pesticide. Washington, DC American Chemical Society. 653.Google Scholar
Geigle, W. L. and Pugh, L. M. 2007. Homogeneous blends of pesticide granules. in. Proc. 11th IUPAC Int. Cong. of Pest. Chem. Google Scholar
Gianessi, L. P. 2005. Economic and herbicide use impacts of glyphosate-resistant crops. Pest Manag. Sci. 61:241245.Google Scholar
Green, J. M. 1998. Differential tolerance of corn (Zea mays) inbreds to four sulfonylurea herbicides and bentazon. Weed Technol. 12:474477.Google Scholar
Gressel, J. 2005. Problems in qualifying and quantifying assumption in plant prediction models: Resultant simulations can be mistaken by a factor of a million. Crop Prot. 24:10071015.Google Scholar
Gutterson, N. and Zhang, J. Z. 2004. Genomics applications to biotech traits: a revolution in progress. Curr. Opinion Plant Sci. 7:226230.Google Scholar
Hall, J. C., Donnelly-Vanderloo, M. J., and Hume, D. J. 1996. Triazine-resistant crops: the agronomic impact and physiological consequences of chloroplast mutation. in Duke, S.O., ed. Herbicide-Resistant Crops. Boca Raton, FL CRC. 107126.Google Scholar
Hall, L., Topinka, K., Huffman, J., and Davis, L. 2000. Pollen flow between herbicide-resistant Brassica napus is the cause of multiple-resistant B. napus volunteers. Weed Sci. 48:688694.Google Scholar
Hammer, P. E., Hinson, T. K., Duck, N. B., and Koziel, M. G. 2005. Methods to confer herbicide resistance. U.S. patent 0,204,436.Google Scholar
Haughn, G. and Somerville, C. R. 1987. Selection for herbicide resistance at the whole plant level. in LeBaron, H.M., Mimma, R.O., Hineycutt, R.C. and Duesing, J.H., eds. Biotechnology in Agricultural Chemistry. Washington, DC American Chemical Society. 98107.Google Scholar
Hayes, K. R., Gregg, P. C., Gupta, V. V. S. R., Jessop, R., Lonsdale, W. M., Sindel, B., Stanley, J., and Williams, C. K. 2004. Identifying hazards in complex ecological systems. Part 3: Hierarchical holographic model for herbicide tolerant oilseed rape. Environ. Biosafety Res. 3:109128.Google Scholar
Heap, I. M. 1994. Identification and documentation of herbicide resistance. Phytoprotection 75:8590.Google Scholar
Heap, I. M. 2006. The international survey of herbicide resistant weeds. http://www.weedscience.com. Accessed: September 15, 2006.Google Scholar
Heap, I. M. and LeBaron, H. 2001. Introduction and overview of resistance. in Powles, S.B. and Shaner, D.L., eds. Herbicide Resistance and World Grains. Boca Raton, FL CRC. 122.Google Scholar
Herman, P. L., Behrens, M., Chakraborty, S., Chrastil, B. M., Barycki, J., and Weeks, D. P. 2005. A three-component dicamba O-demethylase from Pseudomonas maltophilia, Strain DI6: gene isolation, characterization, and heterozygous expression. J. Biol. Chem. 280:2475924767.Google Scholar
Hilgenfield, K. L., Martin, A. R., Mortensen, D. A., and Mason, S. C. 2004. Weed management in glyphosate resistant soybean system: Weed species shifts. Weed Technol. 18:284291.Google Scholar
Holm, L. G., Plunknett, D. L., Pancho, J. V., and Herberger, J. P. 1977. The World's Worst Weeds: Distribution and Biology. Honolulu University Press of Hawaii. 609.Google Scholar
Ismail, B. S., Chuah, T. S., Salmijah, S., Ten, Y. T., and Schumacher, R. W. 2002. Germination and seedling emergence of glyphosate-resistant and susceptible biotypes of goosegrass. [Eleusine indica (L) Gaertn]. Weed Biol. Manag. 2:177185.Google Scholar
James, C. 2004. Preview: Global Status of Commercialized Biotech/GM Crops: 2004. Ithaca, NY ISAAA ISAAA Briefs No. 32. http://www.isaaa.org/.Google Scholar
Keenan, R. J., Siehl, D. L., Gorton, R., and Castle, L. A. 2005. DNA shuffling as a tool for protein crystallization. Proc. Natl. Acad. Sci. USA 102:88878892.Google Scholar
Kishore, G. M., Padgette, S. R., and Fraley, R. T. 1992. History of herbicide-tolerant crops, methods of development and current state of the art—emphasis on glyphosate tolerance. Weed Technol. 6:626634.Google Scholar
Kishore, G. M. and Shah, D. M. 1988. Amino acid biosynthesis inhibitors as herbicides. Annu. Rev. Biochem. 57:627663.Google Scholar
Laplante, J. 2006. Characterization of resistance to acetolactate synthase inhibitors in green foxtail: molecular genetics and biochemical basis. Weed Sci. Soc. Am. Abstr. 46:255.Google Scholar
Lebrun, M., Sailland, A., Freyssinet, G., and Degryse, E. 1997. Mutated 5-enolpyruvylshikimate-3-phosphate synthase, gene coding for said protein and transformed plants containing said gene. World Patent Appl. No. 9,704,103.Google Scholar
Lee, K. Y., Townsend, J., Tepperman, J., Black, M., Chui, C. F., Mazur, B., Dunsmuir, P., and Bedbrook, J. 1988. The molecular-basis of sulfonylurea resistance in tobacco. EMBO J. 7:12411248.CrossRefGoogle ScholarPubMed
Lee, L. J. and Ngim, J. 2000. A first report of glyphosate-resistant goosegrass (Eleusine indica (L.) Gaertn) in Malaysia. Pest Manag. Sci. 56:336339.Google Scholar
Li, X. and Nicholl, D. 2005. Development of PPO inhibitor-resistant cultures and crops. Pest Manag. Sci. 61:277285.Google Scholar
Lorraine-Colwill, D. F., Powles, S. B., Hawkes, T. R., Hollinshead, P. H., Warner, S. A. J., and Preston, C. 2003. Investigations into the mechanism of glyphosate resistance in Lolium rigidum . Pestic. Biochem. Physiol. 74:6272.Google Scholar
Loux, M., Stachler, J., Johnson, B., Nice, G., Davis, V., and Norby, D. 2005. Biology and management of horseweed. Pages 12. Ohio State Technical Bulletin ID-323.Google Scholar
Madsen, K. H. and Streibig, J. C. 2004. Benefits and risks of the use of herbicide-resistant crops. in Labrada, R., ed. Weed Management for Developing Countries. Rome Food and Agricultural Organization of the United Nations. 245255.Google Scholar
Mallory-Smith, C. A., Thill, D. C., and Dial, M. J. 1990. Identification of sulfonylurea herbicide-resistant prickly lettuce (Lactuca serriola). Weed Technol. 4:163168.CrossRefGoogle Scholar
Mallory-Smith, C. A., Thill, D. C., Alcocer-Ruthling, M., and Thompson, C. 1992. Growth comparisons of sulfonylurea resistant and susceptible biotypes. in Proceeding of the First International Weed Control Congress. Volume 2. Melbourne, Australia Weed Science Society of Victoria. 301303.Google Scholar
Marshall, M. W., Al-Khatib, K., and Maddux, L. 2000. Weed community shifts associated with continuous glyphosate applications in corn and soybean rotation. Proc. West. Soc. Weed Sci. 53:2225.Google Scholar
Matringe, M., Sailland, A., Pelissier, B., Roland, A., and Zind, O. 2005. p-hydroxyphenylpyruvate dioxygenase inhibitor-resistant plants. Pest Manag. Sci. 61:269276.Google Scholar
Mazur, B. J. and Falco, S. C. 1989. The development of herbicide resistant crops. Annu. Rev. Plant Physiol. 40:441470.Google Scholar
Mueller, T. C., Mitchell, P. D., Young, B. G., and Culpepper, A. S. 2005. Proactive versus reactive management of glyphosate-resistant or -tolerant weeds. Weed Technol. 19:924933.Google Scholar
Nandula, V. K., Reddy, K. N., Duke, S. O., and Poston, D. H. 2005. Glyphosate-resistant weeds: current status and future outlook. Outlooks Pest Manag. 12:183197.Google Scholar
Neve, P. and Powles, S. 2005. Recurrent selection with suboptimal rates of the herbicide diclofop-methyl result in a rapid increase in population level resistance in Lolium rigidum . Theor. Appl. Genet. 110:11541166.Google Scholar
Norris, R. F. 1999. Ecological implications of using thresholds for weed management. J. Crop Prod. 2:3158.Google Scholar
Owen, M. D. K. 1997. Risks and benefits of weed management technologies. in DePrado, R., Jorrin, J. and Garcia-Torres, L., eds. Weed and Crop Resistance to Herbicides. London Kluwer Academic. 291297.Google Scholar
Owen, M. D. K. 2001. World maize/soybean and herbicide resistance. in Powles, S.B. and Shaner, D.L., eds. Herbicide Resistance and World Grains. Boca Raton, FL CRC. 101163.Google Scholar
Owen, M. D. K. 2002. Glyphosate resistant waterhemp in Iowa. Proc. North Cent. Weed Sci. Soc. 57:210.Google Scholar
Owen, M. D. K. and Zelaya, I. A. 2005. Herbicide-resistant crops and weed resistance to herbicides. Pest Manag. Sci. 61:301311.Google Scholar
Padgette, S. R., Kolac, K. H., Delannay, X., Re, D. B., Lavallee, B. J., Tinius, C. N., Rhodes, W. K., Otero, Y. I., Barry, G. F., and Eicholtz, D. A. 1995. Development, identification, and characterization of glyphosate-tolerant soybean line. Crop Sci. 35:14511461.Google Scholar
Padgette, S. R., Taylor, N. B., Nida, D. L., Bailey, M. R., MacDonald, J., Holden, L. R., and Fuchs, R. L. 1996. The composition of glyphosate-tolerant soybean seeds is equivalent to that of conventional soybeans. J. Agric. Food Chem. 126:702716.Google Scholar
Park, K. W., Mallory-Smith, C. A., Ball, D. A., and Muellar-Warrant, G. W. 2004. Ecological fitness of acetolactate synthase inhibitor-resistant and -susceptible downy brome (Bromus tectorum) biotypes. Weed Sci. 52:768773.Google Scholar
Patzoldt, W. L., Tranel, P. J., and Hager, A. G. 2002. Variable herbicide responses among Illinois waterhemp (Amaranthus rudis and A. tuberculatus) populations. Crop Prot. 21:707712.Google Scholar
Pedersen, B. P., Neve, P., Andreasen, C., and Powles, S. B. 2007. Ecological fitness of a glyphosate resistant Lolium rigidum population: growth and seed production along a competition gradient. Basic Appl. Ecol. 8:258268.Google Scholar
Pérez, A. and Kogan, M. 2003. Glyphosate-resistant Lolium multiflorum in Chilean orchards. Weed Res. 43:1219.Google Scholar
Pline, W. A., Wu, J., and Hatzios, K. K. 1999. Effects of temperature and chemical additives on the response of transgenic herbicide-resistant soybeans to glufosinate and glyphosate applications. Pestic. Biochem. Physiol. 65:119131.Google Scholar
Pline-Srnic, W. 2005. Technical performance of some commercial glyphosate-resistant crops. Pest Manag. Sci. 61:225234.Google Scholar
Powles, S. B., Lorraine-Colwill, D. F., Dellow, J. J., and Preston, C. 1998. Evolved resistance to glyphosate in rigid ryegrass (Lolium rigidum) in Australia. Weed Sci. 46:604607.Google Scholar
Powles, S. B. and Preston, C. 2006. Evolved glyphosate resistance in plants: biochemical and genetic basis of resistance. Weed Technol. 20:282289.Google Scholar
Pratley, J. E., Urwin, N. A. R., Stanton, R. A., Baines, P. R., Broster, J. C., Cullis, K., Schafer, D. E., Bohn, J. A., and Krueger, R. W. 1999. Resistance to glyphosate in Lolium rigidum: I. Bioevaluation. Weed Sci. 47:405411.Google Scholar
Reddy, K. N., Rimando, A. M., and Duke, S. O. 2004. Aminomethylphosphonic acid, a metabolite of glyphosate, causes injury in glyphosate-resistant soybeans. J. Agric. Food Chem. 52:51395143.Google Scholar
Saari, L. L., Cotterman, J. C., and Thill, D. C. 1994. Resistance to acetolactate synthase inhibiting herbicides. in Powles, S.B. and Holt, J.A., eds. Herbicide Resistance in Plants: Biology and Biochemistry. Boca Raton, FL CRC. 83139.Google Scholar
Sebastian, S. A., Fader, G. M., Ulrich, J. F., Forney, D. R., and Chaleff, R. S. 1989. Semidominant soybean mutation for resistance to sulfonylureas. Crop Sci. 29:14031408.Google Scholar
Gupta, A. Sen, Heinen, J. L., Holaday, A. S., Burke, J. J., and Allen, R. D. 1993. Increased resistance to oxidative stress in transgenic plants that overexpress chloroplast Cu/Zn superoxide dismutase. Proc. Natl. Acad. Sci. USA 90:16291633.Google Scholar
Siehl, D. L., Castle, L. A., Gorton, R., Chen, Y. H., Bertain, S., Cho, H. J., Keenan, R., Liu, D., and Lassner, M. W. 2005. Evolution of a microbial acetyltransferase for modification of glyphosate: a novel tolerance strategy. Pest Manag. Sci. 61:235240.Google Scholar
Friesen, L. J. Shane and Hall, J. C. 2004. Herbicide resistance: moving beyond simple explanations. in Inderjit, I., eds. Weed Biology and Management. Amsterdam Kluwer. 211225.Google Scholar
Shaner, D. L. 2000. The impact of glyphosate-tolerant crops on the use of other herbicides and on resistance management. Pest Manag. Sci. 56:20326.Google Scholar
Shaner, D. L., Feist, D. A., and Retzinger, E. J. 1997. SAMOA™: one company's approach to herbicide-resistant weed management. Pestic. Sci. 51:367370.Google Scholar
Shaner, D. L. and O'Connor, S. L. 1991. The Imidazolinone Herbicides. Boca Raton, FL CRC. 290.Google Scholar
Simarmata, M., Bughrara, S., and Penner, D. 2005. Inheritance of glyphosate resistance in rigid ryegrass (Lolium rigidum) in California. Weed Sci. 53:615619.Google Scholar
Smeda, R. J. and Schuster, C. L. 2002. Differential sensitivity to glyphosate among biotypes of common waterhemp (Amaranthus rudis Sauer). in Jacob, S., Dodd, H.J. and Morre, J.H., eds. 13th Australian Weeds Conference. Perth, Australia Council of Australian Weed Science Societies. 642.Google Scholar
Snipes, C. E. 2005. Management practices to sustain Roundup Ready cotton production. in. Proceedings of the Beltwide Cotton Conference 31633164.Google Scholar
Stetter, J. 1994. Herbicides Inhibiting Branched Chain Amino Acid Biosynthesis: Recent Developments. New York Springer-Verlag. 219.Google Scholar
Streber, W. R., Kutschka, U., Thomas, F., and Pohlenz, H. D. 1994. Expression of a bacterial gene in transgenic plants confers resistance to the herbicide phenmedipham. Plant Mol. Biol. 25:977987.Google Scholar
Surov, T., Aviv, D., Aly, R., Joel, D. M., Goldman-Guez, T., and Gressel, J. 1998. Generation of transgenic asulam-resistant potatoes to facilitate eradications of parasitic broomrapes (Orobanche spp.) with the su gene as the selectable marker. Theor. Appl. Genet. 96:132137.Google Scholar
Tan, S. Y., Evans, R. R., Dahmer, M. L., Singh, B. K., and Shaner, D. L. 2005. Imidazolinone-tolerant crops: history, current status and future. Pest Manag. Sci. 61:246257.Google Scholar
Tranel, P. J. and Wright, T. R. 2002. Resistance of weeds to ALS-inhibiting herbicides: What have we learned? Weed Sci. 50:700712.Google Scholar
VanGessel, M. J. 2001. Glyphosate-resistant horseweed from Delaware. Weed Sci. 49:703705.Google Scholar
Veldhuis, L. J., Hall, L. M., O'Donovan, J. T., Dyer, W., and Hall, J. C. 2000. Metabolism-based resistance of a wild mustard (Sinapis arvensis L.) biotype to ethametsulfuron-methyl. J. Agric. Food Chem. 48:29862990.Google Scholar
Vila-Aiub, M. M., Neve, P., and Powles, S. B. 2005. Resistance cost of a cytochrome P450 herbicide metabolism but not an ACCase target site mutation in a multiple resistant Lolium rigidum population. New Phytol. 167:787796.Google Scholar
Volenberg, D. S., Patzoldt, W. L., Hager, A. G., and Tranel, P. J. 2004. Has waterhemp become harder to control with glyphosate? Proc. North Central Weed Sci. Soc. 59:84.Google Scholar
Weersink, A., Llewellyn, R. S., and Pannell, D. J. 2005. Economics of pre-emptive management to avoid weed resistance to glyphosate in Australia. Crop Prot. 24:659665.Google Scholar
Westra, P., Belles, D., and Hanson, B. 2005. Weed shifts after six years in glyphosate tolerant corn and soybeans. Weed Sci. Soc. Am. Abstr. 45:9.Google Scholar
Willis, A. D., Mortimer, A. M., Putwain, P. D., and Moss, S. R. 1997. Variation in cross-resistance in blackgrass (Alopecurus myosuroides) within and between populations: Implications and management. Brighton Crop Protection Conf. 2:675676.Google Scholar
Wright, T. R., Lira, J. M., Merlo, D. J., and Hopkins, N. 2005. Novel herbicide resistance genes. World Patent Appl. No. 107,437.Google Scholar
York, A. C., Beam, J. B., and Culpepper, A. S. 2005. Control of volunteer glyphosate-resistant soybean in cotton. J. Cotton Sci. 9:102109.Google Scholar
Yuan, C. I., Mou-Yen, C., and Yih-Ming, C. 2002. Triple mechanisms of glyphosate-resistance in a naturally occurring glyphosate-resistant plant Dicliptera chinensis . Plant Sci. 163:543554.Google Scholar
Zelaya, I. A. and Owen, M. D. K. 2005. Differential response of Amaranthus tuberculatus (Moq ex DC) JD Sauer to glyphosate. Pest Manag. Sci. 61:936950.Google Scholar
Zelaya, I. A., Owen, M. D. K., and VanGessel, M. J. 2004. Inheritance of evolved glyphosate resistance in Conyza canadensis (L.) Cronq. Theor. Appl. Genet. 10:5870.Google Scholar