Rep. Artur Davis lost the Democratic gubernatorial primary Tuesday, ending his bid to become the first African-American to hold Alabama's top job.

Davis lost to state Agriculture Commissioner Ron Sparks, who pulled in 64 percent of the vote to the congressman's 36 percent, according to unofficial results.

Sparks' long-shot victory may be attributed to low voter turnout among blacks who did not go to the polls for Davis at the same levels they did in 2008 for President Obama.

The Birmingham News explains:

Even Sparks seemed to have doubted his chances of winning, having at one point mulled dropping out of the race and running for Congress. Sparks now credits those second thoughts to his campaign manager at the time. 

But Sparks didn't drop out, and on Tuesday he was rewarded with one of the more   remarkable upsets in Alabama primary history. In unofficial results, Sparks beat U.S. Rep. Artur Davis of Birmingham.

While votes were still being counted and results were not complete, Davis didn't wait   for the final tally. He conceded the race to Sparks shortly before 10 p.m. in front of somber supporters in downtown Birmingham.

"This is not exactly the speech I'd planned to give tonight," Davis said.

He congratulated Sparks and noted that both men had been reared by single mothers with the help of a grandmother in challenging circumstances and had risen to the level of running for governor.

"It says something about the American Dream," Davis said.

Davis urged supporters to rally around the Democratic nominee and give him their support. He said he still believed in the basic themes of his campaign: the need for constitutional reform and economic improvement.

"A better champion will come along," he said.

Sparks' victory denied Davis' bid to make history by becoming the first black in Alabama to win his party's nomination for governor. 

Sparks, 57, won the nomination in large part by campaigning on a single issue: his support for legalizing, regulating and taxing Las Vegas-style gambling in Alabama.