UPDATE 2-Early voting peaceful in Guinea election
* Election could be turning point for Guinea
* Analysts warn of violence if result rejected
* Rivals come from two main ethnic groups
(Recasts with start of voting, voter quote)
By Richard Valdmanis and Saliou Samb
CONAKRY, Nov 7 (Reuters) - Guineans voted peacefully on Sunday in the decisive second round of a presidential election aimed at returning the country to civilian rule, with no early reports of trouble after a campaign marked by ethnic tension.
The election is the mineral-producing West African state's first free vote since independence from France in 1958 and, if it passes smoothly, could improve stability in a fragile neighbourhood known as Africa's "coup belt".
The run-up to the vote was turbulent, with at least one killed and dozens injured in clashes between rival political camps, and rows over electoral preparations leading to delays to the second round since the first vote was held in June.
"I am hopeful for a free, fair and peaceful vote that will end years of rule with impunity," said Alpha Conde, a veteran opposition politician who faced former premier Cellou Dallein Diallo in the election, said as he cast his vote in the Mafanco suburb of the capital Conakry.
"We are proud today. It has been 50 years with dictators and impunity," said Amadou Diallo, an unemployed resident of Conakry as he headed to vote. "This will change today."
International observers were hopeful electoral officials had laid the groundwork for a credible vote to reduce the chances the results -- due to published a few days later -- will be rejected by the loser over allegations of fraud.
Reuters witnesses who toured Conakry said the first few hours of voting were proceeding without delays.
General Yakubu Gowon, leading the observation mission of the U.S.-based Carter Center human rights group, issued a statement saying that the polling stations he had visited appeared calm.
The stakes are high for the world's top supplier of aluminum ore bauxite, whose resources have attracted billions of dollars of planned investment from companies like Vale (VALE.N) and Rio Tinto (RIO.AX) but where instability has hampered development.
The vote ends nearly two years of junta rule since a December 2008 coup, and comes close on the heels of Ivory Coast's Oct. 31 first round of presidential elections, which passed peacefully despite some worries of turmoil.
Diallo and Conde each represent one of Guinea's two most populous ethnic groups, the Peul and Malinke, respectively.
For a profile on Guinea [ID:nLDE6A607Q]
For a timeline on recent events [ID:nLDE6A607V]
Diallo took 43.69 percent in June's first round -- making him the favourite -- while Conde took just 18.25 percent and later complained of fraud undermining his score. Ethnic strains run deep between Peul supporters of Diallo and Malinke supporters of Conde after recent clashes, with neither group likely to easily accept their candidate's loss.
"If Conde loses, the election will have been fraudulent," said Amadou Camara, a Malinke taxi driver and Conde supporter.
The Peul, meanwhile, have long believed other ethnic groups have ganged up to keep them out of power since independence.
Analysts have warned that ethnic tensions pose some risk to neighbours Liberia, Sierra Leone, and Ivory Coast -- all of which are still recovering from recent civil wars and which share Peul and Malinke populations. (Editing by Mark John and Mark Heinrich)