WASHINGTON and OTTAWA -- The United States has ratcheted up its assault on the Canadian Wheat Board (CWB) by slapping preliminary duties as high as 8.15 per cent on $400-million worth of Canadian wheat it claims is being dumped across the border. As with numerous other high-profile disputes with its largest trading partner, Ottawa vowed to vigorously fight yesterday's U.S. Commerce Department decision, which pushes interim duties on Canadian wheat to more than 12 per cent. Ralph Goodale, the minister responsible for the CWB, said the duties are part of a pattern of "trade harassment" by the U.S. government, and...