HANOVER, Germany (Reuters) - Germany’s Greens broke with their broad-church tradition on Saturday by electing as leaders two figures from the centrist wing, a move that would make them more palatable as coalition partners for Chancellor Angela Merkel’s conservatives.

German Chancellor and leader of the Christian Democratic Union (CDU) Angela Merkel gives a statement before the start of coalition talks at the Christian Democratic Union (CDU) party headquarters in Berlin, Germany, January 26, 2018. REUTERS/Christian Mang

A move to the center could heighten pressure on the Social Democrats (SPD), who are attempting to use their leverage as the conservatives’ last remaining possible coalition partner to put a left-wing stamp on a future government.

Long among Europe’s most successful environmentalist parties, the Greens have moved from radical origins to become a major center-left force, governing in coalition with the Social Democrats (SPD) for seven years to 2005.

But talks last year on forming a Merkel-led three-way coalition with the pro-business Free Democrats (FDP) broke down, with complaints that some of the Greens’ environmentalist demands were too costly.

The party, which elects a male and a female co-leader, has traditionally split the two posts between a centrist candidate and a more radical figure from the “Fundi” wing.

But at a congress in the northern city of Hanover, delegates elected Robert Habeck and Annalena Baerbock, both from the party’s “Realo” wing, a move that could create fiercer competition for the beleaguered SPD.

“If we see the supposed contradiction between radicalism and statesmanship as an opportunity and not as a weakness then today really is just the start,” said Baerbock, adding that she wanted to end dirty coal generation while addressing social dislocation in mining regions.

The SPD, which scored its worst result since 1933 in September’s national election, is trying to win back disillusioned voters by securing worker-friendly spending commitments from the conservatives, with whom they are in talks on forming a coalition.

With the collapse of talks on forming a “Jamaica” coalition - named because the three parties’ colors match the island nation’s flag - a renewed SPD alliance became Merkel’s best chance of securing a fourth term.

But a more centrist Green party could open space for renewed talks on a Jamaica coalition if current coalition talks fail.

One of two “people’s parties” that dominated Germany’s post-war history, the SPD polled just 19 percent on the eve of coalition talks with the conservatives, placing it only eight points ahead of the Greens.