AWB has followed the lead provided by the US wheat futures markets and cut its 2008/09 Estimated Pool Returns by $15 a tonne due.
The EPR range for APW wheat now stands at $365-$385/t (FOB, GST exclusive) and the Western Australian noodle grade wheat is $370-$390/t.
AWB Australia commodity division general manager, Mitch Morison, said US wheat futures had dropped significantly over the last fortnight in response to a range of factors.
Mr Morison said that although the Australian dollar was also weaker, it was not enough to offset the futures decline.
"The market is showing a lot of volatility and responds rapidly to changes," he said.
"US wheat futures and cash sales prices had been rallying strongly on the back of solid export sales of US wheat to Iran, but once the prices went up, the sales rapidly dropped off and US wheat futures went into decline.
"The US futures market has also taken some encouragement from recent rain in parts of Australia.
"Crop estimates in the EU, Russia and Ukraine have all been revised significantly higher in recent weeks, placing further downward pressure on the market."
Mr Morison said the market will would for direction in the next few weeks from the US Department of Agriculture's September 12 report of World Agricultural Supply and Demand, and ABARE's Australian crop report due on September 16.