CANBERRA, June 18 (Reuters) - Chicago wheat futures dropped on Tuesday to their lowest levels in two months as speculators responded to an accelerating U.S. harvest and crop-boosting rainfall in the Black Sea region by selling contracts.

Corn and soybean futures edged higher.

FUNDAMENTALS

* The most-active wheat contract on the Chicago Board of Trade (CBOT) was down 0.2% at $5.90-1/4 a bushel, as of 0027 GMT, after falling to $5.88-1/2, the lowest since April 23.

* CBOT soybeans rose 0.4% to $11.62-1/4 a bushel and corn was trading 0.4% higher at $4.45-1/2 a bushel.

* Wheat futures surged to a 10-month high of $7.20 last month as dry conditions and frosts in Russia, the biggest exporter, pushed down harvest estimates.

* But prices have since plunged by around 18% as the U.S. harvest began pouring supply into the market and rainfall eased concerns about Black Sea crops.

* Russian wheat export prices for the new harvest have declined significantly from a week ago as concerns over the impact of bad weather subsided, analysts said.

* The U.S. Department of Agriculture said on Monday the country's winter wheat harvest was 27% complete, up from 12% a week ago and ahead of the five-year average of 14%.

* Expectations for a record harvest in Romania should partly offset lower output in larger producers France and Germany, where torrential rain has hit crops.

* China, meanwhile, expects another bumper summer grain harvest this year, a spokesperson from the National Bureau of Statistics said.

* In corn markets, U.S. farmers are holding onto their production in the hope of better prices despite few signs of an improvement in the market.

* Weekly condition ratings for U.S. corn and soybean crops fell last week, but were still the highest for this time of the season in several years, U.S. government data show.

* In soybeans, data showed that the U.S. soy crush rebounded in May from a seven-month low in April and topped most trade estimates.

* Commodity funds were net sellers of CBOT corn, wheat and soybean futures on Monday, traders said.

MARKETS NEWS

* A gauge of global stocks rose for the first time in three sessions on Monday, powered by a rally in U.S. equities, while U.S. Treasury yields climbed after a sharp drop in the prior week as investors awaited comments from Federal Reserve officials.

(Reporting by Peter Hobson; Editing by Sherry Jacob-Phillips)