MANKATO-September 6, 2012-(KMKO)-DuPont Pioneer has announced a $2.5 million expansion of its Mankato corn research center to accommodate the continued growth of research programs at the facility.  Pioneer first established a research station in Mankato in 1958 and built a center in the current location in 1966.  The 24,000-square-foot expansion will take place in two phases and is scheduled to be complete by mid-2013.