Since the mid-1980's, Monsanto Company has been developing the Roundup Ready^TM gene to confer crop tolerance to Roundup Ultra^® herbicide in multiple crops including cotton. Cotton plants with the Roundup Ready^TM gene have the EPSPS gene from Agrobacterium spp. strain CP4. This gene produces an EPSPS synthase which is not sensitive to Roundup Ultra^®. Cotton plants containing this gene are therefore tolerant to over the top or post directed applications of Roundup Ultra^® while weeds remain sensitive and will be controlled by the herbicide.

Roundup Ready^TM cotton is tolerant to topical applications of Roundup Ultra^® from ground crack through the 4 leaf stage of development. Post directed techniques may be used to apply Roundup Ultra^® in Roundup Ready^TM cotton which is 5 leaves or larger. The maximum rate of Roundup Ultra^® which may be used in early season topical or post directed applications is 0.75 lbs ae/A and multiple applications may be made. Roundup Ultra^® herbicide may also be applied topically to cotton after it has reached 20% boll crack.