Bloomberg: The snow is piled waist-deep outside the Southern Manitoba Convention Centre as more than 400 farmers gather to consider the once-unthinkable: growing corn on the Canadian prairie. At one end of the packed auditorium last month in Morris, home of the Red River Wild hockey club, an Ohio farmer brought in by DuPont Co. (DD:US) is making a presentation with a slide that reads Ear Count 101. At the other end, Deere & Co. is showing off tractors and other equipment from a booth while Daryl Gross explains...