CHICAGO, Nov 3 (Reuters) - Chicago soybean futures climbed on Tuesday on export optimism and a slower-than-expected U.S. harvest pace, traders said.

Wheat firmed as traders monitored dryness in U.S. and Russian growing belts, while corn traded higher on continued hopes of China buying.

The most-active soybean contract on the Chicago Board of Trade (CBOT) settled 12 cents higher at $10.64-1/4 per bushel, the contract's biggest single-day gain since Oct. 14.

CBOT wheat ended up 1/2 cent to $6.08 per bushel while CBOT corn added 3-1/2 cents to $4.01 per bushel.

Soybeans climbed on news that Brazil, the world's biggest soy exporter, is buying U.S. soybeans as the country grapples with rising prices of domestic food staples.

Analysts said corn, rice, wheat and cotton exports to Brazil are possible from the United States, and more likely than soybean sales.

"It's going to be difficult, with the GMO (soybean) varieties that are locked out of Brazil, to be able to re-export," said Mike Zuzolo, president of Global Commodity Analytics. "Everything they take is going to have to be for domestic consumption."

Both corn and soybean futures were supported by lower-than-expected harvest progress numbers reported by the U.S. Department of Agriculture on Monday. The U.S. harvest was 82% complete for corn and 87% complete for soybeans, ahead of the crops' respective five-year averages, but both fell short of average analyst expectations.

U.S. voters headed to the polls on Election Day to cast ballots for President Donald Trump or Democratic rival Joe Biden.

Some analysts say the outcome will not affect the recent spate of grain buying from top importer China.

"No matter who’s president, China still needs to feed their hog herd," said Dan Smith, senior risk manager at Top Third Ag Marketing. (Reporting by Christopher Walljasper; Additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by David Gregorio)