Where Will Wheat Grow?

One of our readers sent us a link to a startling graphic showing that the wheat-growing region in North America will have moved entirely north of the US/Canadian border by 2050. The graphic is being passed around on environmental blogs. Its intermediate source appears to be a BBC story, New Crops Needed To Avoid Famines; ultimate credit goes to the International Maize and Wheat Improvement Center, but we can't find the source story or the graphic on their website.