Authorities in Mexico have denied an application from seed giant Monsanto Co. to expand to pilot planting projects of genetically modified corn in northern Mexico, arguing that more experimental planting is needed to ensure the GM crops won’t affect native corn varieties. [...] Reynaldo Alvarez Morales said Wednesday companies will have to plan at least another cycle of small plots of about 2 acres (1 hectare), before they can move on to ”pilot” plots of as much as 50 hectares (124 acres).