Traders have been likening Minneapolis-traded spring
The yellow metal fell $100 an ounce from its day high, amid a bout of profit-taking.
Minneapolis spring wheat tumbled too, closing down 2.6% at $9.26 a bushel for September delivery, if still well above an August low under $8 a bushel.
The catalyst was data from north of the border in Canada, also spring wheat country, which indicated that supplies of the grain, while looking disappointing in the US, may not end up in a such a shortage after all.
Official statisticians pegged Canada's all-wheat crop above 24m tonnes, some 500,000 tonnes more than traders had expected, citing decent summer weather.
"That means that world wheat supplies are growing a little more than US Department of Agriculture projected last month," Darrell Holaday at Country Futures said.
"This has kept the wheat market at bay somewhat today," and may prove of long-term significance, according to the UK grain arm of a major European commodities house.
"This figure is important for the direction of the milling wheat market going forward as Canadian wheat is predominantly spring milling wheat, so all eyes on what quality they get," the merchant said.
Still, wheat on other markets proved somewhat more resilient, on the day at least. Chicago wheat for September closed down 1.1% at $7.94 ¼ a bushel.
Kansas hard red winter wheat lost a modest 0.7% to close at $8.35 a bushel for September delivery, amid those lingering concerns about conditions for sowing in the southern Plains next month.
"Early planting concerns in Kansas City are starting to spark that market," Matthew Pierce at PitGuru said.
And Paris wheat for November ended 0.5% lower at E206.75 a tonne, gaining support from continuing concerns over the rain-delayed German harvest.
London's November contract closed unchanged at £169.00 a tonne.
But, back in US, the default move was down, amid a mixed performance in other markets, with New York
New York crude shed 0.3% to stand at $85.18 a bushel in late deals.
Sure, some supportive news kept coming in, notably from the ProFarmer tour of Midwest crops.
"Recent stories from the tour have not been real encouraging," for neither
Latest talk has corn yields in Illinois, the second-ranked producing state, looking, at best, average.
Nor do forecasts show imminent rains to refresh crops, although there is some talk of rainfall in 10 days' time or so.
Furthermore, it is dry in northern China too, continuing to "stress the developing crop, and bringing more world yield issues to the table", PitGuru's Mr Pierce said.
But, as US Commodities said: "The problem with the market is that most of the bull news could be in the market. Rationing is taking place at these levels. The market is maturely bullish.
"Remember at one time the trade thought the 2010-11 corn ending stocks would be around 600m bushels. We are now at 940m bushels and growing."
December corn hit a contract high of $7.48 ¾ a bushel only to close at $7.43 a bushel, down 0.5 cents on the day.
November soybeans mirrored the action, hitting a one-month top of $14.03 ¼ a bushel, but closed at $13.93 ½ a bushel, down 0.2%.
In New York,
The lot closed at 30.18 cents, down 2.1% on the day, as the top prompted a rash of sell-downs by speculators who have a large net long position in the sweetener, a factor the market has feared might make them trigger happy with sales – eager to get their profit-taking in first.
Or, at least, of healthy supplies smuggled from top producer Ivory Coast.
Prices gained some support from "higher Chinese prices last night and relative stability in yarn", Mike Stevens, the veteran Louisiana-based cotton analyst, said.
Furthermore, strong prices are begetting more trade buying.
"Talk is that some mills are thought to be starting to get a bit nervous with the market's staying power above 100 cents a pound," Mr Stevens said.