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Technical buying, Argentina drought worries lift corn

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Soybeans mixed as traders weigh supplies and demand

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Wheat sinks to 15-month low on weak U.S. exports

(Rewrites throughout, adds quote, updates prices, changes byline, changes dateline from SINGAPORE/PARIS)

CHICAGO, Jan 10 (Reuters) - U.S. corn futures rebounded on Tuesday in a technical and bargain-buying bounce from three-week lows as drought threatened the Argentine harvest and active exports pared down Brazil's old-crop supply.

Soybeans were mixed while wheat fell to its lowest in 15 months on good global supplies and weak demand for U.S. shipments.

Grain traders are squaring positions ahead of U.S. Department of Agriculture (USDA) crop data on Thursday.

Chicago Board of Trade March corn was up 5 cents at $6.57-3/4 a bushel at 11:58 a.m. CDT (1758 GMT) after earlier touching a three-week low of $6.48-1/4. Buying accelerated as the benchmark contract broke through technical chart resistance at its 20- and 30-day moving averages.

March soybeans were 3/4 cent lower at $14.87-3/4 a bushel. CBOT March wheat was 7-1/4 cents lower at $7.34-1/4 a bushel after hitting a low of $7.20-1/2 earlier in the session, the lowest for a most active contract since October 2021.

"Corn has been beaten down pretty good since the beginning of the year and it was bound for a little technical buying and bargain shopping," said Terry Reilly, senior commodities analyst with Futures International.

"We're also seeing some positioning across the board ahead of the USDA report," he said.

The USDA is expected to cut its corn and soy production outlook for drought-hit Argentina but also raise its estimate of U.S. grain and soybean supplies.

Hot, dry weather is expected across Argentina's crop belt over the next 10 days, adding stress on an already drought-diminished crop, according to a Commodity Weather Group forecast.

Sluggish export demand has weighed on U.S. grain markets, particularly wheat, amid strong competition in the global market and large crops around the world. Production in India could hit an all-time high, traders said. (Additional reporting by Naveen Thukral in Singapore and Sybille de La Hamaide in Paris; Editing by Sherry Jacob-Phillips, Shailesh Kuber and Barbara Lewis)