After a lower overnight and bearish start to the day's trade, the grains rebounded Wednesday to close higher across the board.

At the close, March wheat was 9 1/2 cents higher at $6.16 1/2 per bushel, while January soybeans were 9 1/4 higher at $11.53 3/4, according to Barchart.com. March wheat ended the day 9 1/4 cents higher at $6.17 per bushel.

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The grains continued their surge on growing weather concerns in South America. Rains have fallen in Brazil and Argentina in the last 24 hours, but not enough to ease weather worries enough to stem the rally.

• Talk: Did the rains fall?
• Slideshow: Adding up S.A. rainfall

"We may get some rains in S.A. in the next days, weeks, months. But, saying that and assuming everthing turns out perfect weather-wise until the end of the season, we already lost 8 to 10 millions tons of beans in Argentina, Paraguay and Brazil combined," says Agriculture.com Marketing Talk member agmr. "Early-planted beans are almost dead in a wide area in those 3 countries."