* Other candidates stand down in favour of Sall
* Wade bid for third term triggered protests
* Sall is former prime minister under Wade
DAKAR, March 10 (Reuters) - Senegal opposition candidates who combined won over 65 percent of the ballot in a first round presidential election rallied on Saturday behind Macky Sall to challenge incumbent President Abdoulaye Wade in the second round on March 25.
All 12 other candidates who ran against Wade in the first round, and civil society group M-23, which has been calling on Wade to step down, pledged to campaign and call on their supporters to vote for Sall.
Wade’s controversial bid for a third term triggered street protests in the normally calm West African state ahead of the Feb. 26 first round, and galvanised the opposition against him.
Octogenarian Wade, scored 34.8 percent of the first-round votes, ahead of Sall’s 26.6 percent, falling short of the outright majority he needed to avoid a run-off.
“Macky (Sall) is our standard bearer, we have all individually decided to support him. We are convinced that we will win this battle,” said Amath Dansokho, honorary president of the M-23 movement which has been leading street protests against Wade.
Former prime minister Moustapha Niasse, who came third in the first round vote, told a joint press conference in Dakar that 12 years ago, many of them had backed Wade, but he had turned his back on some of their shared principles.
“We are here today to support Macky Sall,” Niasse said.
“Each of us must go back to our bases and whip up support so as to better the score of the first round,” he said.
Sall, a former prime minister in Wade’s government, had called on the other opposition parties to back him and has won the support of hugely popular Senegalese musician Youssou N’Dour.
Sall said he will not betray the trust the candidates had placed on him and reiterated his promise to fight poverty, reform and strengthen Senegal’s political institutions while maintaining a clear separation of powers between the executive branch and other branches of government. (Reporting by Bate Felix and Diadie Ba; Editing by Michael Roddy)