GRAINS-Wheat firms, lingers near 18-month high on global supply concerns

* Wheat rises on concerns of Russian and French supplies

* Corn firms, soybeans edge lower

SYDNEY, Jan 23 (Reuters) - U.S. wheat futures edged higher on Thursday as fears of tighter global supplies pushed prices towards a near 18-month high.

Corn firmed, drawing support from wheat, while soybeans inched lower.

The most-active wheat futures on the Chicago Board of Trade were up 0.2% at $5.78-3/4 a bushel by 0339 GMT. In the previous session, it closed 0.7% lower after hitting an Aug. 2, 2018 high of $5.92-1/2 a bushel.

“There are some weather concerns in the Black Sea, which has the market a bit worried,” said Phin Ziebell, agribusiness economist, National Australia Bank.

Russia, the world’s largest wheat exporter, said last week it was looking to set a non-tariff quota for grain exports of 20 million tonnes for January-June.

The proposal by the agriculture ministry is yet to be approved by the government, which unexpectedly resigned last week. It is unclear when the new government will be fully formed and how it will react to the proposed export restrictions.

Meanwhile, rail and port strikes in France have raised the risk of reduced export availability in the European Union’s biggest wheat supplier.

A French grain industry body said this week that industrial action over pension reform had left 450,000 tonnes of grain, worth some 100 million euros ($111 million), blocked at French ports.

Corn futures rose 0.1% to $3.89-1/4 a bushel, having gained 0.3% in the previous session.

Soybean futures fell 0.1% to $9.12-1/2 a bushel, having closed down 0.3% on Wednesday when prices hit a Dec. 16 low of $9.13 a bushel.

Brazil’s soybean farmers have harvested only 1.8% of the soybean area so far this season, agribusiness consultancy AgRural said on Monday, reducing the ideal window for planting of the country’s second corn that is sowed after the oilseed is collected. (Reporting by Colin Packham; editing by Uttaresh.V)