Complex sentence: In October 2014 the US EPA registered Dow's "Enlist Duo" maize, which is genetically modified to be resistant to both glyphosate and 2,4-D, in six states.
Split into simpler sentences: In October 2014, the US EPA registered Dow's "Enlist Duo" maize. Enlist maize is genetically modified to be resistant to both glyphosate and 2,4-D, in six states.