* Wheat down for second week as U.S. Plains set for relief * Soybeans ease from near 7-year high, S. America weather eyed * Corn subdued as U.S. planting indications awaited (Updates with European trading, changes byline/dateline) By Gus Trompiz and Naveen Thukral PARIS/SINGAPORE, March 12 (Reuters) - Chicago wheat futures extended losses on Friday to a one-month low as rain forecast for dry parts of the U.S. Plains eased supply concerns. Soybean edged lower as it moved back from a near seven-year high this week, with the market weighing increased estimates of Brazil"s soybean harvest against a declining outlook for Argentina. Corn also eased, with traders awaiting indications about U.S. spring planting trends and fresh signs of Chinese demand. The most-active wheat contract on the Chicago Board Of Trade (CBOT) was down 0.4% at $6.40-1/4 a bushel by 1026 GMT, after earlier touching its lowest since Feb. 12 at $6.38. "The upcoming rainfall to the U.S. Hard Red Winter wheat regions, including the very western third, continues to weigh on prices," Tobin Gorey, director of agricultural strategy at the Commonwealth Bank of Australia in Sydney, said. Significant rain expected in the coming days in a swathe of the U.S. Plains could bring relief for parched crops as they enter the key spring growth phase. The improved moisture outlook for U.S. wheat coincides with reports of better growing conditions in top exporter Russia, along with a favourable situation in the European Union. An import tender by Egypt on Thursday also tempered supply concerns, as it showed a large number of offers, including bids of Russian wheat despite a recent export tax. Egyptian state buyer purchased 360,000 tonnes of Romanian wheat in the tender. CBOT soybeans were down 0.3% at $14.08-3/4 a bushel, on course for their first weekly loss in five. CBOT corn was down 1.0%. The Buenos Aires Grains Exchange lowered its estimates of Argentina"s soybean harvest to 44 million tonnes and its corn forecast to 45 million tonnes, below its previous forecasts of 46 million tonnes for each crop, citing dry conditions. But several forecasters have increased estimates for Brazil"s ongoing soybean harvest, despite rain delays. Concern that renewed outbreaks of African swine fever in China could weaken demand for livestock feed like soy has weighed on the market, countering support from a global rally in vegetable oils including soyoil. Prices at 1026 GMT Last Change Pct End Ytd Pct Move 2020 Move CBOT wheat 640.25 -2.25 -0.35 640.50 -0.04 CBOT corn 533.25 -5.25 -0.97 484.00 10.18 CBOT soy 1408.75 -4.75 -0.34 1311.00 7.46 Paris wheat May 224.00 -0.50 -0.22 210.50 6.41 Paris maize Jun 215.75 -1.00 -0.46 198.75 8.55 Paris rape May 517.75 -1.25 -0.24 412.00 25.67 WTI crude oil 65.93 -0.09 -0.14 48.52 35.88 Euro/dlr 1.19 -0.01 -0.58 1.2100 -1.54 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 Rashmi Aich and Alexander Smith)