* Incumbent Republican's exit a plus for Democrats

* Wide-open field of challengers expected

By Scott Malone

BOSTON, Nov 10 (Reuters) - President Barack Obama's Democratic Party, which lost two state governorships last week, drew hope for winning the governor's office in Connecticut next year after the Republican incumbent said she would not run for re-election.

Jodi Rell, in office since 2004, said on Monday she would not seek another term, setting the stage for a wide-open contest between a field of Democrats led by Secretary of State Susan Bysiewicz and Republicans including Rell's No. 2, Michael Fedele.

"It can't help but be a plus for the Democrats, because they don't need to run against the incumbent," said Howard Reiter, a political science professor at the University of Connecticut. "She has remained pretty popular."

It has been 18 years since a Democrat occupied the governor's mansion in Connecticut, the state with the highest per-capita income in the United States.

Ruling parties tend to lose ground in U.S. mid-term elections and the Democrats are looking to hold on to their majority in the two houses of the U.S. Congress as well as their state positions in the elections in November, 2010.

Republican victories in governor's races in New Jersey and Virginia last week were seen as showing the limits to the clout of the popular Obama, who is under pressure over the war in Afghanistan and the slow economic recovery.