Mount Vernon, Iowa - Laura Krouse is stumped.She does not know how her old-fashioned, open-pollinated corn picked up traces of newfangled, genetically modified corn two years ago, or why her corn tested clean of the GMO genes a year ago.All she knows is that it is critical for her business - Abbe Hills Open Pollinated Seed Corn - that the corn be free of the genes from genetically altered corn.</p><p><a href="http://desmoinesregister.com/business/stories/c4789013/21933370.html">DesMoinesRegister</a>