Glyphosate Behavior in a Transgenic Glyphosate- and Soybean Cyst Nematode-Resistant Soybean Variety

Abstract

Abstract Soybean (Glycine max L. Merr.) varieties containing multiple traits that impart resistance to stress factors (e.g., herbicides and diseases) need to be investigated to determine if all resistance responses remain fully functional under simultaneous stress exposure. Experiments were conducted in the greenhouse to investigate the effects of soybean cyst nematode (SCN) infection on glyphosate uptake, distribution, and activity in a soybean variety containing genes for SCN and glyphosate resistance (R). A glyphosate-, SCN-susceptible variety (S) was included for comparison. Glyphosate absorption was not affected by SCN infection in either variety. Glyphosate distribution in the R variety was altered slightly by SCN infection when the herbicide was applied 9 days after inoculation (DAI), but this effect diminished as herbicide application timing was delayed to 18 DAI or later, possibly due to increased expression of the SCN resistance response and lower levels of SCN infection. Glyphosate did not affe...