PARIS (Reuters) - Right-wing heavyweight Xavier Bertrand quit France s main conservative party, The Republicans, on Monday, highlighting the challenges its new chief will face in trying to keep the party together.  The move comes a day after party members overwhelmingly elected Laurent Wauquiez as a their new boss, following a campaign during which he said President Emmanuel Macron was too weak on security and immigration.  I don t recognize my political family, so I decided to leave it,  Bertrand, a former health minister and current head of Hauts-de-France, a region in northern France, said on France 2 TV station.  Bertrand s move underlines growing concern among moderate members of The Republicans about the party s direction, after a disastrous presidential campaign that saw its candidate eliminated in the first round.   Some have said Wauquiez was hauling the party too far to the right and running after the National Front, whose leader Marine Le Pen made it to the second round of the presidential election last May.   Xavier Bertrand obviously considers that he has no place (in the party). It s his choice. I respect it,  Wauquiez said on TF1 TV station, in reaction to the news.  I move forward, I look to the future and what I want is to make a new generation emerge, this new right that live to its ideas,  he said.  