U.S. and EU officials begin talks Monday on an ambitious free-trade agreement aimed at generating billions of dollars of new trade. But negotiators must overcome barriers created by cultural and philosophical differences over sectors like agriculture. In Europe, the cultivation of genetically modified crops is banned, while in the U.S., they are a central part of food production. NPR's Jackie Northam visited a farm in Delaware and NPR's Eleanor Beardsley visited one in Burgundy, France, to look at those deep-seated differences. We hear from Jackie first.