GRAINS-Wheat slips to seven-week low on U.S. rain relief

* Rains in southern Plains seen helping drought-hit wheat

* Soybeans also weak with focus on expected U.S. area rise

* Bumper Brazil crop, China trade fears also curb soy prices

(Updating with European trading, changes byline/dateline) PARIS/SINGAPORE, March 28 (Reuters) - Chicago wheat futures extended losses on Wednesday to hit a seven-week low as rains in parts of the U.S. Plains improved prospects for drought-hit crops, putting the focus back on ample global supplies. Soybeans also eased as attention shifted towards U.S. government planting estimates on Thursday that are expected to show soybean acreage expanding and overtaking corn. Corn futures were also slightly lower, with weakness across equity and commodity markets adding to a cautious mood on grain markets before Thursday's U.S. Department of Agriculture (USDA) planting report. The Chicago Board Of Trade most-active wheat contract was down 0.9 percent at $4.45 a bushel by 1107 GMT. It earlier touched its lowest since Feb. 6 at $4.44-1/2. CBOT soybeans eased 0.3 percent to $10.16-3/4 a bushel, while corn also ticked down 0.3 percent, to $3.73 a bushel. "The U.S. winter wheat crop had a pretty tough winter period but spring weather has been favourable," said Phin Ziebell, an agribusiness economist at National Australia Bank. "A large chunk of the rally that we saw in February has gone." Showers crossing the U.S. Plains on Tuesday and more rain expected on Wednesday should alleviate dryness, particularly in southern wheat belts, adding to moisture received last week. The USDA on Monday rated 13 percent of winter wheat in Kansas, the top producer, in good-to-excellent condition, up from 11 percent a week earlier, although still well down from a year ago. In the soybean market, recent price support from severe drought in major exporter Argentina was fading. "While the market is having to digest a constant stream of bad news about Argentina, the estimates for the crop in neighbouring Brazil where harvesting is almost complete are soaring to ever new highs," Commerzbank analysts said. "The prospect of an even larger U.S. soybean acreage ... is also weighing on the price." Agroconsult, a Brazilian consulting firm, raised on Tuesday its estimate of the country's soybean harvest to 118.9 million tonnes, from 117.5 million previously. The USDA's widely followed acreage projections are expected by analysts to show U.S. soybean plantings for 2018 at a record-high of 91.1 million acres and corn plantings at 89.4 million acres, down from 90.2 million in 2017.

Analysts also expect the USDA to report record-high March 1 corn and soybean stocks, reflecting several years of bumper harvests. Concern that trade tensions between the United States and China could hamper soybean flows between the two countries was also keeping Chicago futures in check. Chinese importers are paying record harvest-time premiums for Brazilian soybeans, fearing disruption to shipments from the United States.

Prices at 1107 GMT

Last Chang Pct End Ytd Pct e Move 2017 Move CBOT wheat 445.00 -4.00 -0.89 427.00 4.22 CBOT corn 373.00 -1.00 -0.27 350.75 6.34 CBOT soy 1016.75 -2.75 -0.27 961.75 5.72 Paris wheat May 162.75 -0.75 -0.46 162.50 0.15 Paris maize Jun 163.25 0.00 0.00 163.50 -0.15 Paris rape May 345.25 -2.25 -0.65 352.75 -2.13 WTI crude oil 64.79 -0.46 -0.70 60.42 7.23 Euro/dlr 1.24 0.00 -0.08

Most active contracts - Wheat, corn and soy US cents/bushel, Paris futures in euros per tonne

(Reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by Richard Pullin and Mark Potter)