Oct 3 (Reuters) - Brazil holds elections on Sunday to choose a successor to President Luiz Inacio Lula da Silva, who is barred by law from seeking a third consecutive term.
Dilma Rousseff of the ruling Workers' Party has seen her support slip in recent days but still holds a wide lead in opinion polls. If she fails to win more than 50 percent of the vote on Sunday, a runoff between the top two vote-getters will be held on Oct. 31.
Here are short profiles on each of the three leading candidates.
DILMA ROUSSEFF, WORKERS' PARTY
* Lula chose the relatively unknown civil servant Rousseff as presidential candidate for the party he founded three decades ago, citing her managerial experience and technical capacity.
* Rousseff, 62, proposes a mix of market-friendly policies with a strong role for the state in economic development.
* As chief of staff and energy minister under Lula, Rousseff was in charge of managing many of Brazil's infrastructure projects and preparing the legislative framework to develop vast new oil reserves.
* She chaired the board of directors of state-owned oil company Petrobras.
* A former leftist militant, Rousseff was dubbed the iron lady for her curt and demanding management style. In public, the technocrat lacks Lula's folksy charm and at times struggles to connect with her audience.
* This is the first time she is running for elected office, although she has held several other executive jobs, such as secretary of energy in the southern state, Rio Grande do Sul.
* The daughter of a well-to-do Bulgarian immigrant, Rousseff was born into a middle-class family and studied economics at the University of Minas Gerais.
* She got her first taste for politics during the 1964 military coup, when university campuses were rife with student protest movements.
* Rousseff joined a radical leftist resistance group but never engaged in armed conflict. She was imprisoned for three years and tortured by her military captors.
* She was treated for lymphoma cancer early last year but has been given a clean bill of health.
JOSE SERRA, BRAZILIAN SOCIAL DEMOCRACY PARTY (PSDB)
* The 68-year-old Serra is one of the most experienced politicians in Brazil. He held numerous elected posts, including as Sao Paulo mayor and Sao Paulo state governor.
* Serra is running for a six-party, center-right coalition, but is trailing front-runner Rousseff by about 20 percentage points in opinion polls.
* He studied engineering and holds a Ph.D in economics from Cornell University.
* Serra became widely known and popular as health minister in the administration of President Fernando Henrique Cardoso (1995-2002) when he took on big pharmaceutical firms, threatening to break their patents and forcing them into price cuts. He was previously planning minister under Cardoso.
* Serra first ran for president in 2002, losing to Lula in a runoff.
* He established a reputation as an efficient manager but is not especially charismatic nor a rousing orator. He struggles to connect with voters and can appear arrogant.
* While the PSDB is seen as more open to markets and the private sector, Serra himself favors a strong government and has a leftist background that would not be out of place in Rousseff's Workers' Party. He is linked to a school of thought that advocates economic planning, a strong state, capital controls and import substitution. As planning minister, he clashed with the pro-market wing in the Cardoso government.
* Serra's father was an Italian immigrant who sold fruit in Sao Paulo to support his family and pay for Serra's education. He got his first taste of politics as a leader in the student movement in 1962 and 1963.
* Brazil's military dictatorship forced Serra into exile in Chile and the United States from 1964 to 1978.
MARINA SILVA, GREEN PARTY
* A former environment minister under Lula and a renowned Amazon defender, Silva is running for the Green Party. She trails a distant third in opinion polls.
* Silva is a former rubber tapper from the Amazon who only learned to read and write as a teenager and paid for her schooling by working as a maid.
* The frail and soft-spoken Silva has been running on a platform of clean government and sustainable development.
* Her proposals range from bicycle paths and water treatment to greener farming technologies and fiscal discipline.
* Her vice presidential running mate is wealthy businessman Guilherme Leal, owner of Brazilian cosmetics company Natura.
* Silva, 52, stepped down as Lula's environment minister in May 2008 amid disagreement with the country's powerful farm lobby over her Amazon protection policies.
* An evangelical Christian, Silva began her political career working alongside legendary environmental activist Chico Mendes, who was murdered in 1988.
* The Green Party, long a fringe party in Brazil with little clout, made headlines in 2008 when its candidate, Fernando Gabeira, nearly won the mayoralty of Rio de Janeiro.
* Silva has for years struggled with health issues including hepatitis, malaria and metal poisoning. She was hospitalized on several occasions, including as environment minister. (Compiled by Raymond Colitt; Editing by Kieran Murray)
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