(Recasts; updates with U.S. trading, adds new analyst quote, changes byline, dateline; pvs PARIS/SINGAPORE)
CHICAGO, Dec 8 (Reuters) - U.S. wheat futures eased to contract lows on Friday, capping a week of five straight days of declines that saw the market shed 4.5 percent of its value.
Soybean futures also were weaker while corn was close to unchanged.
A forecast for bigger-than-expected wheat production in Canada issued earlier this week cast a bearish tone over the market that traders were still processing. It underlined the idea that U.S. exporters will continue to struggle to find business with overseas buyers, traders said.
"The world is amuck in wheat right now and regardless of how many acres we plant this year, our wheat is not competitive," said Ed Duggan, senior risk management specialist at Top Third Ag Marketing in Chicago.
Strength in the dollar added to the bearish pressure on wheat.
At 12:30 p.m. CST (1830 GMT), Chicago Board of Trade March soft red winter wheat futures were down 3 cents at $4.18-1/2 a bushel. The contract hit a low of $4.17-3/4 a bushel earlier in the session.
K.C. hard red winter wheat futures also notched a contract low.
CBOT March corn was 1/2 cent higher at $3.52 a bushel. Corn futures have fallen 1.9 percent this week.
CBOT January soybean futures were 4 cents lower at $9.88 a bushel. Soybean futures have fallen 0.7 percent this week after rising in the previous four weeks.
Export demand for soybeans has picked up this week after a slow start to the marketing year.
The U.S. Department of Agriculture earlier on Friday said that private exporters reported the sale of 268,000 tonnes of soybeans for delivery to China during the 2017-18 marketing year. The government also disclosed another 129,000-tonne sale to unknown destinations for 2017-18 and a 66,000-tonne sale to unknown destinations for 2018-19.
Traders said concerns about a bumper crop in South America cutting into the U.S. share of the export market limited enthusiasm about the recent sales.
Consultancy AgRural on Friday raised its forecast for 2017-18 Brazil soybean production to 112.9 million tonnes from 110.2 million.
And forecasts for some much needed rain in Argentina in the coming weeks added pressure to soybeans on Friday. (Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; editing by Elaine Hardcastle and Diane Craft)