GRAINS-Chicago grains higher with weather and tariffs in focus

PARIS/BEIJING, Feb 20 (Reuters) - Chicago corn, wheat and soybeans rose on Thursday, recouping losses from the previous session with support from a weaker dollar while traders assessed South American weather and comments from U.S. President Donald Trump about China.

The most-active corn contract on the Chicago Board of Trade (CBOT) Cv1 was up 1.0% at $5.02-1/2 a bushel by 1224 GMT, near a 16-month peak of $5.04-1/2 struck on Wednesday before prices ended lower.

A fall in the dollar index =USD underscored favourable export prospects for U.S. corn, which fuelled the cereal's recent rally along with doubts over South America's harvest outlook.

"Grain fundamentals are supportive via corn's strong export demand and global export competitiveness," Peak Trading Research said in a note.

Any shortfall in South American production in the coming months could reinforce export demand for U.S. corn.

Temperatures in Argentina are forecast to top 35 degrees Celsius (95°F) in the coming days and would affect almost the country's entire agricultural area, the Buenos Aires Grains Exchange said on Wednesday.

Slow planting of Brazil's main corn crop has added to concern about South American supply.

While various U.S. plans to impose extra tariffs have stirred concerns about retaliation against the country's agricultural exports, there was some relief in commodity markets after Trump said on Wednesday that a trade deal with China was possible and he expected Chinese President Xi Jinping to visit the United States.

China is by far the world's biggest soybean importer and has been a major corn and wheat buyer.

CBOT soybeans Sv1 added 0.8% to $10.39-1/2 a bushel while CBOT wheat Wv1 rose 0.4% to $6.09 a bushel.

The wheat market has been monitoring cold weather in Russian and U.S. plains, though snow cover was expected to limit potential frost damage to wheat plants.

Weather risks have increased attention on tightening supply in Russia, where the government has imposed an export quota for the rest of the season.

While milling wheat exports have been moderate, the rally in corn prices has raised expectations that some demand may shift towards wheat.

"Global wheat supplies are already forecast near multi-year lows, with tightening of the wheat-corn spread suggesting wheat feed demand could increase," Bergman Grains Research said in a note.