<p style="text-align: justify;">Cotton is the United States and the worlds leading fiber crop. In the US for the 2006 production year, cotton was grown on 15.3 million acres, the major producing states being Texas (6.4 million acres), Georgia (1.4 million acres), Mississippi (1.2 million acres), Arkansas (1.2 million acres), North Carolina (0.9 million acres) and Tennessee (0.7 million acres). The world total planted area in 2005-2006 was 85 million acres, for a production of 114.1 million bales (24.8 million tons).</p>

<p style="text-align: justify;">Cotton is grown in the United States using mechanized practices for planting and harvesting. Cultural practices, including irrigation and crop rotation, and herbicides are employed to control weeds. Weed management is critical to maximum cotton yield and herbicides are used on most cotton acreage grown in the United States. The grower is interested in applying a broad weed spectrum herbicide for weed control, that does not injure the crop, is cost effective, and has positive environmental attributes.</p>

<p style="text-align: justify;">Glyphosate normally exerts herbicide activity by binding and inactivating EPSPS (5-enolpyruvylshikimate-3-phosphate synthase), an enzyme that is essential for the synthesis of proteins in plants. Cotton line GHB614 has been genetically modified (GM) for tolerance to glyphosate herbicides by expression in the plant of a modified <i>epsps</i> gene from corn (<i>Z. mays</i>), <i>2mepsps</i>, which introduces two amino acid changes in the enzyme. The amino acid changes in the 2mEPSPS protein significantly lower the sensitivity to glyphosate, allowing the enzyme to continue to function in the presence of the herbicide. Glyphosate has been shown to be an efficacious weed control system when utilized with glyphosate-tolerant cotton. Broad spectrum weed control is usually achieved with a single application for pre-plant burndown, and then one in-season application. GlyTol cotton event GHB614 has a broad application window which may be used to apply glyphosate, giving growers increased flexibility in their herbicide programs.</p>
