GRAINS-Russian drought sends US wheat surging above $6/bu

* Wheat soars on dim Black Sea export prospects

* Ukraine sees smaller exportable surplus

* Corn retreats from early gains on profit-taking

* For short-term technical view, click on (Recasts with U.S. trading; changes dateline from previous SINGAPORE/MADRID, changes byline)

By Julie Ingwersen

CHICAGO, July 22 (Reuters) - Front-month wheat futures on the Chicago Board of Trade broke above $6.00 a bushel for the first time in 13 months on Thursday as a spreading drought reduced crop prospects in key exporter Russia.

CBOT wheat for September delivery peaked at $6.10 per bushel, up 3.7 percent on the day and the highest level for a front month on continuous charts since June 2009.

Wheat came off its highs by midsession and CBOT corn turned lower, erasing an early rally as traders booked profits, while soybeans clung to modest gains.

As of 10:55 a.m. CDT (1555 GMT), September wheat was up 6-3/4 cents at $5.95 a bushel.

CBOT September corn was down 1-3/4 cents at $3.78 a bushel while August soybeans were up 1-1/2 cents at $10.16-3/4 a bushel.

A weaker dollar supported grains, as well as other dollar-denominated commodities including crude oil and gold. The Reuters-Jefferies CRB index, a global commodities benchmark, hit a one-month high as oil and copper prices surged.

The dollar fell more than 1 percent against the euro after U.S. housing data and better-than-expected euro zone manufacturing and services data revived appetite for risk.

But grain markets remained focused on the Black Sea region, where drought is forcing major exporters -- Russia, Ukraine and Kazakhstan -- to cut their 2010 forecasts further. As a result, their exportable surplus may shrink.

"European and Russian weather are driving the market," said Glenn Hollander, of Chicago cash merchant Hollander & Feuerhaken.

"We can talk all we want about some hot and dry (U.S.) weather here longer-term, but the big problems are in the Russian and European grain areas," Hollander said.

Ukraine said it would likely cut its grain exports in the 2010/11 market year to 16 million metric tonnes, from 21.5 million in 2009/10.

"Wheat is holding up very well. There is more concern obviously with the drought. At the moment there is still more news to come and that is what's helping the wheat market," said Jonathan Barratt, managing director of Commodity Broking Services in Sydney.

The Russian government will sell grain from its stocks to domestic animal and poultry breeders, as well as processors, to cushion damage from a severe drought, the Agriculture Ministry said in a statement on Wednesday. (Additional reporting by Sam Nelson in Chicago, Naveen Thukral in Singapore, Martin Roberts in Madrid, Nigel Hunt in London; Editing by David Gregorio)