(Recasts with rural caucus meeting, plan to ease guns controls)
By Rodrigo Viga Gaier
RIO DE JANEIRO, Oct 24 (Reuters) - Brazil's right-wing presidential front-runner, Jair Bolsonaro, has begun to shape policies and choose high-ranking ministers for the government he plans to form after his expected landslide victory in Sunday's run-off election.
Following a meeting at his home on Wednesday, rural caucus lawmakers said Brazil's agriculture and environment ministries may remain separate, apparently ditching Bolsonaro's plan for a merger that caused a storm of criticism from environmentalists.
"If it's best for Brazil that there is an agriculture and an environment ministry, we will talk about it after the election," his agriculture adviser Nabhan Garcia told reporters, indicating Bolsonaro was open to dropping his campaign promise to farmers.
Downgrading the environment ministry would be seen as contrary to Brazil's commitment to protect the Amazon rainforest, and could hurt Brazil's export market by angering environmentally aware consumers abroad.
But another Bolsonaro promise to the farm lobby, the easing of gun control laws to allow them to arm themselves against rising crime in rural areas, could happen before he takes office on Jan. 1 if he defeats left-wing Workers Party candidate Fernando Haddad as expected.
The Speaker of Brazil's lower chamber of Congress, Rodrigo Maia who aims to stay in the job, said he intends to move ahead with the issue after Sunday's vote.
"We have a well balanced bill. People want security on their farms and there are a lot of robberies and land invasions," Maia told reporters in Rio.
Bolsonaro, a former Army captain who has vowed to crackdown on corruption and crime, has said he will change the law to typify land invasions as criminal acts of terrorism.
Bolsonaro has been criticized for campaigning on generalities and avoiding debate on precise policy plans. He is expected to follow free-market economic policies under economist and investor Paulo Guedes, his pick for finance minister.
Selections to head ministries and state-owned companies will be announced within 30 days after the election, the head of Bolsonaro's PSL party, Gustavo Bebianno, said on Tuesday.
Bolsonaro also intends to make changes in the leadership of state firms including Petroleo Brasileiro SA (Petrobras) and Centrais Eletricas Brasileiras SA (Eletrobras), Bebianno added.
"The menu already has many names. To avoid speculation, we will only give them after the election," he said.
Bebianno said central bank President Ilan Goldfajn was a "good name" to continue and Bolsonaro had not ruled him out. Bolsonaro and Guedes will make the decision, Bebianno said.
Controversy surrounding the use of mass online messaging in support of Bolsonaro has failed to derail his substantial lead over Haddad. An Ibope opinion poll on Tuesday showed Bolsonaro had 57 percent voter support to Haddad's 43 percent, slightly narrower than 59-41 percent in the previous survey.
Bolsonaro has denied Haddad's accusations that he asked supporters to fund mass messaging on the mobile messaging application WhatsApp, which would violate campaign laws. Brazil's top electoral court last Friday approved the opening of a probe into the matter.
Bolsonaro, a seven-term congressman, has vowed to fight to let users forward text, audio and video messages over WhatsApp to hundreds of recipients. WhatsApp owner Facebook Inc said on Tuesday it had no plans to change its restrictions in the country that limit message forwarding to 20 recipients at a time. (Reporting Rodrigo Viga Gaier in Rio de Janeiro, Jake Spring and Anthony Boadle in Brasilia; Editing by David Gregorio)