CBOT December wheat closed down 4 cents at $3.13 per bushel, after hitting a contract low at $3.12, below the previous low of $3.14-1/2. Deferred months ended 2-1/2 to 4-1/4 cents lower.
Funds sold at least 2,000 contracts, CBOT traders said, while funds sold at least 5,000 lots in Kansas City.
Volume was estimated by the CBOT at 36,378 futures and 6,893 options.
December wheat on the Kansas City Board of Trade fell through several support levels as traders liquidated long positions. Funds hold a large net long position in KCBT wheat and were beginning to roll December positions forward.
The steep declines in Kansas City led wheat prices lower in Minneapolis and Chicago.
"We hung in there early in the day pretty well, because Chicago is on the oversold side. But, when the other wheat exchanges started to break, the Chicago market just couldn't ignore that," Prudential Securities analyst Shawn McCambridge said.
The sell-off pushed CBOT wheat deeper into oversold territory. The nine-day relative strength index for the December contract ended Wednesday at 25. Traders view a reading of 30 or below as one indication of an oversold market.
A lagging export pace and generally satisfactory crop weather in the US winter wheat belt added to the bearish sentiment in the wheat market.
Overnight export business featured South Korea buying 20,000 tonnes of US wheat.
The Delta region of the soft red winter wheat belt got rain recently, which should help improve pre-winter development. The area had been dry and in need of moisture. The Midwest crop belt was in better condition, traders said.
Midwest soft red winter wheat basis bids were mostly steady and farmer selling was slow.