Grain futures dropped Wednesday on the Chicago Board of Trade. Wheat for December delivery dropped 18.75 cents to $6.66 a bushel; December corn fell 6.25 cents to $4.9375 a bushel; December oats slid 10 cents to $3.28 a bushel; while soybeans for November delivery tumbled 14 cents to $10.96 a bushel. Business - Chicago Board of Trade - Bushel - Wheat - Oat