SÃO PAULO, Brazil — Though Dilma Rousseff is a political novice and lacks the charisma of her former boss, President Luiz Inácio Lula da Silva, voters appear likely to make her the first woman to be president of Brazil in Sunday’s election.

Opinion surveys show her leading by a wide margin and suggest that she could get more than 50 percent plus one vote of the valid vote, enough to squeak by and avoid a runoff. Polls opened at 8 a.m. in Brazil on Sunday, as 135.8 million Brazilians began voting to decide on a new president, 27 governors and dozens of federal and state representatives.

Ms. Rousseff, 62, was able to ride Mr. da Silva’s popularity and make the election essentially a referendum on his eight years in office, a period of widespread prosperity that cemented the country as a rising global player.

“This turned out to be a predictable plebiscite, a thumbs-up for the Lula years,” said Timothy J. Power, director of the Latin American Center at the University of Oxford.