* Wheat slips on pressure from U.S. winter wheat harvest
* Rains in Australia seen improving wheat crop condition
* U.S. corn, soybean crops benefit from wet weather (Adds details, quotes)
SINGAPORE, June 28 (Reuters) - Chicago wheat futures edged lower on Thursday, falling for four in five sessions as ample global supplies and pressure from harvest of the U.S. winter crop weighed on the market.
Corn and soybeans lost ground ahead of a key U.S. government report due on Friday.
The most-active wheat contract on the Chicago Board Of Trade was down 0.5 percent at $4.86-1/4 a bushel, as of 0236 GMT, having closed 1.1 percent higher on Wednesday.
Soybeans slipped 0.4 percent to $8.85-1/2 a bushel and corn dipped 0.2 percent to $3.72-1/2 a bushel.
"The USDA's report is coming up and it is expected to raise production estimate on corn, beans given the ideal weather in much of the U.S. Midwest," said Phin Ziebell, agribusiness economist, National Australia Bank.
"There are concerns over trade dispute."
Wheat is facing pressure from ongoing U.S. winter wheat harvest and falling prices in Russia.
The U.S. Department of Agriculture late on Monday said the U.S. winter wheat harvest was 41 percent complete, while the Kansas harvest was 52 percent finished, ahead of the state's five-year average of 32 percent.
Australia's drought-hit grain-producing areas are expected to get some rains.
In Ukraine's southern and central regions, farmers have harvested around 2.7 million tonnes of grain from the 2018 harvest and the yield averaged 3.06 tonnes per hectare, the agriculture ministry said on Wednesday.
Soybean prices could find some support on hopes that trade tensions between the United States and China would abate soon.
U.S. President Donald Trump said on Wednesday he will use a strengthened national security review process to thwart Chinese acquisitions of sensitive American technologies, a softer approach than imposing China-specific investment restrictions.
The agricultural markets are also bracing for the U.S. Department of Agriculture's acreage and quarterly stocks reports on Friday.
Analysts surveyed by Reuters on average expect the USDA to raise estimate of U.S. 2018 corn and soybean plantings from its March forecast, and to report multi-year highs in U.S. June 1 corn and soy stockpiles.
Commodity funds were net buyers of CBOT wheat and soyoil futures contracts on Wednesday, net sellers of corn and soymeal futures and net even in soybean futures, traders said. (Reporting by Naveen Thukral, Editing by Sherry Jacob-Phillips)