* Ample supplies from newly harvested U.S. corn crop weigh * Wheat gains for 4th session in a row on strong demand (Updates prices, adds details) By Naveen Thukral and Sybille de La Hamaide SINGAPORE/PARIS, Sept 28 (Reuters) - Chicago corn slid on Tuesday, easing from a four-week high scaled in the previous session, as a rapid U.S. harvest put pressure on prices. Wheat edged higher after falling in the previous session, while soybeans also lost ground. "Demand for grains is still very strong, and the U.S. harvest has picked up," said Ole Houe, director of advisory services at brokerage IKON Commodities in Sydney. "There is likely to be a bit of harvest pressure starting to show up." The most-active corn contract on the Chicago Board of Trade (CBOT) lost 0.3% to $5.38 a bushel, as of 1044 GMT, after hitting its highest since Aug. 31 at $5.40 a bushel on Monday. Soybeans gave up 0.5% to $12.81-1/2 a bushel, while wheat gained 0.4% to $7.25 a bushel. After the CBOT close on Monday, the U.S. Department of Agriculture (USDA) said the U.S. harvest was 18% complete for corn and 16% for soybeans, both slightly ahead of the five-year averages of 15% and 13%, respectively. Corn rallied in the previous session amid expectations of a recovery in demand. Traders are looking ahead to the USDA"s Sept. 30 quarterly stocks report. Analysts surveyed by Reuters on average expect the government to report U.S. Sept. 1 corn stocks at 1.155 billion bushels, below the 1.187 billion bushels that the USDA projected in its last monthly supply/demand report on Sept. 10. Russian wheat export prices rose for an 11th consecutive week, following higher global benchmarks in Chicago and Paris, analysts said on Monday. On the oilseed complex, Paris-based rapeseed benchmark November hit a new contract high for a sixth consecutive session on Tuesday at 628 euros a tonne, supported by strong biodiesel prices. It has gained 20% in the past two months. Commodity funds were net buyers of CBOT corn, soybean, soymeal and soyoil futures contracts on Monday and net sellers of wheat futures, traders said. COMFUND/CBT Prices at 1044 GMT Last Change Pct Move CBOT wheat 725,00 2,75 0,38 CBOT corn 538,00 -1,50 -0,28 CBOT soy 1281,50 -6,00 -0,47 Paris wheat Dec 255,75 2,50 0,99 Paris maize Nov 227,50 2,50 1,11 Paris rape Nov 627,50 2,00 0,32 WTI crude oil 76,28 0,83 1,10 Euro/dlr 1,17 0,00 -0,13 (Reporting by Naveen Thukral Editing by Subhranshu Sahu and Mark Potter) Our Standards: The Thomson Reuters Trust Principles.