Corn futures at the Chicago Board of Trade were about a penny higher across the board midday Wednesday, supported by firm cash markets, traders said. CBOT March corn was up 1 cent at $1.97 per bushel by 12:15 pm CST (1815 GMT). The deferreds were 1/2 to 1 cent higher. Difficulty in moving grain to US export markets and interior points in the Midwest due to recent storms kept spot corn bids firm.