Lula's presidential candidate slips in Brazil poll

BRASILIA, Sept 22 (Reuters) - Brazilian President Luiz Inacio Lula da Silva's chosen presidential candidate for next year's election lost support in an opinion poll on Tuesday as other potential candidates gained media exposure.

Brazil will hold general elections for president, state governors and legislators in Congress and state assemblies in October 2010.

Lula's chief of staff, Dilma Rousseff, fell 4 percentage points to 14 percent of voter intention since June, an Ibope opinion survey showed.

Sao Paulo state Governor Jose Serra of the centrist opposition PSDB party also fell 4 percentage points but maintained his wide lead with 34 percent.

It is the second poll in the last two weeks showing Rousseff's popularity slipping and will likely raise concern among the government's leading coalition partners, some of whom are considering whether to back Serra.

Rousseff did poorly despite increasing optimism about the economy and a slight improvement in the approval ratings of the government to 81 percent from 80 percent.

Amauri Teixeira, political consultant to the National Confederation of Industry, which published the poll, said Rousseff's potential rivals gained in the polls because they had more media exposure in recent months.

"Dilma had less exposure in the media," Teixeira told a news conference.

Marina Silva, a former environment minister who joined the field of potential contenders after the last Ibope poll in June, took 6 percent of voter intention. Her Green Party featured her prominently in a campaign advertisement in recent weeks.

Ciro Gomes, a former governor from the northeastern Ceara state, gained two percentage points to tie Rousseff at 14 percent, after his Brazilian Socialist Party also ran campaign advertisements on radio and TV networks.

The Ibope survey polled 2,002 people from Sept. 11 to 14 and has a margin of error of plus or minus 2 percentage points.

(Writing by Raymond Colitt, editing by Vicki Allen)