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SAO PAULO (Reuters) - Brazil’s far-right candidate Jair Bolsonaro leads in first-round voting for October’s presidential election, but would lose to most rivals in a likely runoff ballot, according to a poll by Ibope released on Wednesday.

Bolsonaro took 22 percent in the first-round scenario of the survey, the first released since a court ruled jailed leftist Luiz Inacio Lula da Silva could not run.

Environmentalist Marina Silva and leftist Ciro Gomes were tied in second with 12 percent.

Business-friendly candidate Geraldo Alckmin had 9 percent while Fernando Haddad, who will likely replace Lula on the Workers Party ticket, had 6 percent in the Sept. 1-3 poll released by TV Globo.

Next month’s election is the most unpredictable since Brazil’s return to democracy three decades ago. Political corruption investigations have jailed scores of powerful businessmen, politicians and alienated voters who are infuriated with their representatives.

Despite Bolsonaro’s strong first-round polling, Ibope found that in simulated second-round votes, he would lose by 11 percentage points to Gomes, 10 percentage points to Marina Silva, and 9 percentage points to Alckmin, and would beat Haddad by 1 percentage point.

The poll of 2,002 voters has a margin of error of 2 percentage points.