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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #238155
Title: Movement of glyphosate-resistant Palmer amaranth pollen in-field

Author
item SOSNOSKIE, L - University Of Georgia
item Webster, Theodore
item MACRAE, A - University Of Florida
item GREY, T - University Of Georgia
item CULPEPPER, A - University Of Georgia

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/3/2009
Publication Date: 9/1/2009
Citation: Sosnoskie, L.M. Webster, T.M. Macrae, A. Grey, T.L. Culpepper, A.S. 2009. Movement of glyphosate-resistant Palmer amaranth pollen in-field. Proceedings of Southern Weed Science Society. Vol 62:227.

Interpretive Summary:

Technical Abstract: Palmer amaranth (Amaranthus palmeri) is one of the most troublesome weeds of Southern row crops. The objective of this study was to determine if the glyphosate resistance trait could be transferred via pollen in Palmer amaranth. In 2006, a GR Palmer amaranth pollen source population was planted in the center of a 30 ha field. Nine GS plants were planted in plots located at distances of 1, 5, 10, 25, 50, 75, 100, 150, and 200 m from the edge of the source in each of eight directions (N, NE, E, SE, S, SW, W, and NW). In 2007, 15 GS plants were planted in plots at distances of 5, 50, 250, 200, 250, and 300 m from the GR source in the same eight directions. Except for the GR source population, the interior of the field and surrounding acreage (300 m from the field edge) were kept free of Palmer amaranth by chemical and physical means. Offspring from each GS mother plant were treated with 0.5 kg ae/ha glyphosate when the plants were 5-7 cm tall and evaluated 7 and 14 DAT. At 14 DAT, the GR and GS were controlled by glyphosate 4% and 100%, respectively. Resistant offspring were observed at each distance from the GR source in each direction, although the percentage of resistant individuals decreased with increased distance from the pollen source. Approximately 50-60% of the offspring at the 1 m and 5 m distance were resistant to glyphosate; approximately 20-40% of the offspring were resistant at 250 m and 300 m.