CHICAGO, April 17 (Reuters) - U.S. soybean futures rose on Wednesday, bouncing on a round of bargain buying after the most-active July contract hit a six-week low, buoyed in part by firming Brazilian soy markets, analysts said.

But grain futures closed lower. Wheat fell for a third straight session on stiff global competition for export business, and corn sagged in the absence of supportive news.

Chicago Board of Trade July soybeans settled up 4-1/4 cents at $11.64-1/4 per bushel. CBOT July wheat ended down 12-1/2 cents at $5.52-1/4 a bushel and July corn fell 1-3/4 cents to finish at $4.41 a bushel.

Prices for exportable soybeans in top global supplier Brazil have firmed in the past few weeks, analysts said, helping to support U.S. soy values.

"While we can't really post a significant rally, we're seeing our bids follow the South American market," said Karl Setzer of Consus Ag Consulting.

Wheat futures fell about 2% on technical selling along with continued weak export demand for U.S. supplies. The dollar retreated on Wednesday but hovered near a 5-1/2-month high, making U.S. grains less attractive to global buyers.

Meanwhile, Egypt's state grain buyer booked just two 60,000-ton cargoes of Ukrainian wheat at an international tender on Tuesday that attracted numerous offers of wheat originating from the Black Sea region as well as France.

Traders were monitoring dry conditions in winter wheat areas of the southern U.S. Plains and parts of Russia, but forecasts called for rains in portions of both regions.

Ukraine's farm ministry said on Tuesday that the country's grain drop in grain production this would likely fall to about 52 million metric tons this year from 58 million tons in 2023.

For corn, weather in the U.S. Midwest is likely to impact prices more in the coming weeks. Rains were seen slowing planting in the region this week while also replenishing soil moisture. The U.S. corn crop was 6% seeded as of Sunday.

"We're starting to get into more of a weather market," said Setzer. "And that's really going to start elevating our (market) volatility," he said. (Reporting by Renee Hickman; Additional reporting by Peter Hobson and Sybille de La Hamaide; Editing by Sherry Jacob-Phillips, Ravi Prakash Kumar, Jane Merriman and Sandra Maler)