Property tycoon Donald Trump won a substantial boost Friday in his run for US president with the endorsement of New Jersey Governor Chris Christie at a news conference in Forth Worth, Texas, Friday, ahead of the pivotal Super Tuesday primaries in 11 states.  Christie quit the race for the Republican presidential nomination after coming in sixth at the New Hampshire primary. He said he was supporting Trump as the candidate best able to beat Hillary Clinton in the race for president. Both made demeaning remarks about Sen. Marco Rubio, Trump’s leading challenger for the top Republican spot.