Winter wheat futures extend winning streak; corn, soy also firm
* Wheat rises on crop concerns
* Soybeans ease on weaker oil prices, slowing China demand (Recasts, updates with U.S. trading, adds new analyst quote; pvs SINGAPORE/PARIS)
CHICAGO, July 21 (Reuters) - U.S. winter wheat futures rose for the sixth day in a row on Wednesday as adverse weather in key exporting countries raised supply concerns, traders said.
Corn and soybean futures edged higher, with dry soils that threatened to hamper crop development in the U.S. Midwest in focus.
"Corn belt rain events are still basically non-existent in the two-week forecast," Matt Zeller, director of market information at StoneX, said in a note to clients.
MGEX spring wheat futures were down 1.8%, with traders noting that much of the concern about the size of the crop was priced in when the market surged to its highest since November 2012 on Monday.
"There are definitely problems for the U.S. and spring wheat crops but we will get to know how big the problem is when the harvest starts," said one Singapore-based trader, who sells U.S. wheat to millers in Asia.
At 11:16 a.m. CDT (1616 GMT), MGEX spring wheat for September delivery was down 10-1/2 cents at $9.05-1/2 a bushel. Chicago Board of Trade September soft red winter wheat was up 9-3/4 cents at $7.10-1/4 and K.C. September hard red winter wheat was up 8-1/4 cents at $6.68-1/2.
"Western Europe rains return by weekend and remain active much of next week, reducing wheat quality & stalling harvest," Commodity Weather Group said in a note.
Russia's agriculture ministry said on Wednesday that yields from the ongoing harvest of the country's wheat crop averaged 3.45 tonnes per hectare as of July 20, down from 3.47 tonnes per hectare a year earlier.
CBOT December corn was up 3-1/2 cents at $5.69-1/4 a bushel, with the most-active contract peaking at its highest on a continuous basis since July 6.
CBOT November soybeans were 4-1/2 cents higher at $13.93 a bushel. (Additional reporting by Naveen Thukral in Singapore and Sybille de La Hamaide in Paris; Editing by Chizu Nomiyama and David Evans)