U.S. wheat futures dropped for a third straight session as pressure from ample global supplies pushed prices to a nine-day low. The most active wheat futures on the CBOT down 0.3% at $5.23-1/2 a bushel, hovering near a session low of $5.22-1/2 a bushel - the weakest since Nov. 25. Wheat came under pressure amid ample global supplies, despite concerns about dwindling production in Australia.