Today’s column focuses on herbicide resistant GMO technology and next week the potential up- and down- sides of GMOs. While this focuses on herbicide resistant traits produced through genetic engineering, it should be pointed out many herbicide resistant traits have been obtained through conventional breeding techniques. Let’s discuss the trait almost everyone is familiar with – Roundup Ready ® technology.
A more proper term is glyphosate tolerance technology as glyphosate is the common chemical name for Roundup. Roundup is a nonselective herbicide with good activity on almost all common problem field weeds. This column doesn’t deal with developing weed resistance issues.  Roundup Ready crops were developed by isolating the gene from a bacteria that inhibited the activity of glyphosate. Over time with further refinement, the ability for crops to tolerate glyphosate applications has improved allowing a wider window of application.  Current crops grown with this resistance include soybean, corn, canola, alfalfa, cotton, sugar beets, Wheat with this trait was developed but never released due to certain environmental concerns. The vast majority of corn and soybeans planted in the U.S. are glyphosate tolerant.  
Other GMO herbicide tolerance traits out or in development include Glufosinate herbicides and 2,4-D. Crops with one or more herbicide tolerant traits in addition to those mentioned, though not necessarily commercially available yet, include rice. Other herbicide resistance traits found in the agricultural world were obtained through conventional breeding techniques.
While next week’s column will wrap this up with the potential plusses and minuses, let’s take a second to understand why Roundup Ready ® technology was so completely and rapidly adapted.
• Resistance to commonly used herbicides like atrazine and Pursuit. Problem grass and broadleaf weeds like pigweed and crabgrass were becoming resistant and few, if any, cost effective options existed. Some had no effective in season treatments available.
• Effective control of grass weeds in grass crops and broadleaf weeds in broadleaf crops was difficult if not impossible as the growing season progressed.
• Scientific evidence was accumulating indicating the potential environmental hazards and hazards to human health with the excessive use of commonly used herbicides such as atrazine. Glyphosate studies showed it to be much safer and without carryover effects for the next crop.
• The move toward eliminating tillage made weed control more difficult and increased the need for chemical weed control options.
• Eliminating tillage translated into a greater need for crop rotations and increased the need for nonpersistent herbicides to facilitate crop rotations.
There are other factors but this presents the basic idea. Finally next week – why or why not GMO crops?