Receive Breaking News updates as they occur
By Anthony Boadle BRASILIA (Reuters) - Environmentalist Marina Silva would handily beat President Dilma Rousseff if Brazil's October election goes to a runoff, a poll showed on Wednesday, an outcome that seemed unimaginable just a few weeks ago and one that would put an end to 12 years of Workers' Party rule. Silva would win 43.7 percent of the votes to 37.8 percent for Rousseff in a likely second round of voting, said the survey by polling firm MDA. Both polls point to a probable runoff because Rousseff looks unlikely to win more than 50 percent of votes in the Oct. 5 election. Silva has clearly pushed the other main opposition candidate and market favorite, centrist Aecio Neves, into third place and is luring away some of his supporters, the polls showed.