GRAINS-Wheat eases in thin holiday trade but posts 18 pct yearly rise

* Wheat records best annual gain since 2012 on supply drop

* Soy down 7 pct in 2018, buffeted by U.S.-China tussle

* Corn up 7 pct for year as tight wheat supply spurs demand

(Recasts with closing U.S. prices) CHICAGO, Dec 31 (Reuters) - U.S. wheat futures fell more than 1 percent on Monday in thin, technically driven trade, brokers said, but still posted a yearly gain of nearly 18 percent. U.S. soybean futures ended lower, retreating from early advances tied to signs of thawing trade tension between Washington and top global soy buyer China. Corn futures closed narrowly mixed, with nearby contracts fractionally lower in subdued trade ahead of Tuesday's New Year's Day holiday. Chicago Board of Trade March wheat futures settled down 8-1/4 cents at $5.03-1/4 per bushel after touching $5.03, the contract's lowest since Jan. 24, and the lowest for a most-active wheat contract since Nov. 16. CBOT March soybeans ended down 1/2 cent at $8.95 a bushel. March corn finished down 1/2 cent at $3.75 a bushel. Fundamental news was lacking, and brokers and commodity funds focused on squaring positions on the last trading day of the month, quarter and year. "Today is a holiday trade environment, meaning it is all sputters, all risk-off for the year-end. The funds are balancing right now, and selling corn and wheat, and a little soybeans," said Don Roose, president of Iowa-based U.S. Commodities. Despite Monday's slip, CBOT wheat ended 2018 up about 18 percent, its biggest annual rise since 2012, after a sharp fall in production in major exporters Russia, the European Union and Australia, making the grain one of the biggest gainers in commodity markets this year. Corn also rose this year, climbing nearly 7 percent as tightening wheat supply fueled additional demand from livestock feed makers, offsetting concerns about disruption to U.S. shipments to China. CBOT soybeans, however, recorded a 7 percent yearly decline after a plunge in exports to China, coupled with big harvests in the United States and Brazil, weighed on prices. A resumption in Chinese imports of U.S. soybeans this month as part of a negotiated truce between the world's two largest economies helped Chicago prices rebound from a decade low recorded in September. CBOT soybean futures firmed on Monday in early moves after what U.S. President Donald Trump over the weekend described as a "very good call" with China's President Xi Jinping. However, traders remain cautious about the scale of Chinese buying, and a partial shutdown of the U.S. government has added to uncertainty by suspending daily and weekly export sales reports from the U.S. Department of Agriculture.

CBOT soy futures retreated as U.S. cash markets showed few signs of fresh sales, prompting traders to shift their focus to ample world supplies. "The problem with soybeans is you're playing a global shell game. Whether we're shipping soybeans to China, or South America is shipping beans, it doesn't change the global demand structure, and the trade knows that," said Jim Gerlach of A/C Trading.

CBOT settlement prices:

Net Pct Volume

Last change change

CBOT wheat WH9 503.25 -8.25 -1.6 36551 CBOT corn CH9 375.00 -0.50 -0.1 75393 CBOT soybeans SH9 895.00 -0.50 -0.1 55842 CBOT soymeal SMH9 309.90 -3.10 -1.0 33014 CBOT soyoil BOH9 27.85 0.01 0.0 30801

NOTE: CBOT March wheat, corn and soybeans shown in cents per bushel, March soymeal in dollars per short ton and March soyoil in cents per lb.

(Additional reporting by Gus Trompiz in Paris and Emily Chow in Kuala Lumpur; Editing by Dan Grebler and Tom Brown)