By Alberto Dabo
BISSAU (Reuters) - Voters cast their ballots in Guinea Bissau's presidential election on Sunday, which they hope will bring change to the coup-prone nation after weeks of political chaos that sparked violent protests and deadlocked parliament.
President Jose Mario Vaz, 61, is seeking re-election for a second term, and he remains popular among cashew nut farmers in the interior after raising prices for the nuts, the tiny West African country's biggest export earner.
But he faces stiff opposition following a first five-year term marred by political infighting, regular high-level sackings and corruption that came to a head in the run-up to Sunday's election.
"The people of Guinea Bissau are sovereign, and I will respect the verdict of the ballot box," Vaz, wearing a white shirt and black trousers, said after casting his ballot in the capital, Bissau.
"I have accomplished my mission of restoring peace and tranquillity," he said.
Joaquim Branco, the head of the African Union's observer mission, said the early hours of voting had gone smoothly.
Preliminary results are expected on Nov. 28. If there is no outright winner, a second round between the top two candidates will take place on Dec. 29.
While no reliable opinion polls have been published, political analysts say the front-runner is former Prime Minister Domingos Simoes Pereira, 56, a moderniser with a relaxed style whose promise to bolster health and education have made him popular with younger voters in Bissau.
"Guinea Bissau has faced five years of political and institutional crises," Pereira told Reuters in an interview last week, adding that the country needs "a president who is able to create an atmosphere conducive to the restoration of peace and stability."
Guinea Bissau has suffered nine coups or attempted coups since independence from Portugal in 1974, most recently in 2012 when a military takeover disrupted elections. If Vaz completes his term, he will be the first president to do so.
The country's deserted beaches and scattered islands are a draw for adventurous tourists, but its unpoliced waters also provide passage for drug traffickers smuggling cocaine en route from South America to Europe.
The next president will inherit major challenges including widespread poverty and an unstable political system in which the majority party appoints the government but the president has the power to dismiss it. There have been seven prime ministers since Vaz took over in 2014.
Vaz fired premier Aristides Gomes on Oct. 29 and appointed a successor, but Gomes refused to step down. For about 10 days the country had two prime ministers, until Vaz backed down under pressure from the regional bloc ECOWAS.
Ude Mane, a 27-year-old civil servant, said she supported Pereira and his African Party for the Independence of Guinea and Cape Verde (PAIGC), which holds a majority in parliament.
"It is the only party that can pull the country out of its economic slump," she said.
The polls are due to close on Sunday at 1700 GMT.
(Writing by Edward McAllister and Aaron Ross; Editing by Helen Popper and Emelia Sithole-Matarise)