Glyphosate resistance

Resistance to European corn borer, tolerance to the herbicide glyphosate... 

Kleter, G.A., Harris, C.A., Stephenson, G.R. and Unsworth, J. (2008) Comparison of herbicide regimes and the associated potential environmental effects of glyphosate-resistant crops vs. what they replace in Europe. Pestic Manage Sci, 64, 479-488. 

FIGURE 9-31 Glyphosate-resistant soybean plants. The photographs... 

Other developments include the introduction of hybrid lines resistant to glyphosate and glufosinate. Glyphosate-resistance technology was rapidly adopted for soybean, but was more slowly adopted for field corn due to corn s slower canopy closure. Acceptance of glufosinate-resistant weed control technology faced the same obstacles, but has been even less competitive economically due to product cost. 

With the culture of soybean and field com so intimately intertwined throughout the Midwest, changes in soybean weed control affect com weed control as well. One real effect of the widespread adoption of glyphosate-tolerant varieties has been the disincentive to discover and develop new products and new chemistries. Since the advent of glyphosate-resistant soybean, very few products have been developed for that market. 

Several weed species resistant to glyphosate have recently developed in several geographical areas of the United States. This further supports the need for keeping a broad range of herbicides, such as the triazines, available for weed management programs. 

Glyphosate resistance in weeds has already been reported in many areas (at least 15 US states, three Australian states, and seven other countries) and in at least 12 weed species (Pratley et al., 1996 Lorraine-Colwill et al, 1999 Lee and Ngim, 2000 Van Gessel, 2001 Perez and Kogan, 2002 Heap 2006) as summarized in Table 11.5. 

Throughout western Canada and the central Great Plains of North America, volunteer wheat is becoming a more serious problem (Leeson el al., 2005). This may become a special concern if the volunteer wheat is glyphosate-resistant (Harker el al., 2005). There are also many examples of integration of traits from weeds into crops, and there is some evidence of spread from herbicide-resistant crops into weeds (Gressel, 2002). 

Baerson, S.R., D.J. Rodriguez, M. Tran, Y. Feng, N.A. Biest, and G.M. Dill (2002). Glyphosate-resistant goosegrass Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase. Plant Physiol., 129 1265-1275. 

Boutsalis, P. (2001). Herbicide Resistance Action Committee (HRAC) Web page http //plantprotection.org/HRAC Bradshaw, L.D., S.R. Padgette, S.L. Kimball, and B.H. Wells (1997). Perspectives on glyphosate resistance. Weed Technol., 11 189-198. Bravin, F., A. Onofri, G. Zanin, and M. Sattin (2004). Is malathion a useful tool to infer the chlorsulfuron-resistance mechanism in mul-tiresistant Italian populations of Lolium spp. 4th International Weed Science Congress, p. 52, S15MT08P00. 

Cairns, A.L.P. and F.H. Eksteen (2004). Glyphosate and paraquat resistance in weeds of the Western Cape. 4th International Weed Science Congress, p. 20, S17MT08P03. 

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