Nigerian ex-ruler Buhari on course for opposition presidential ticket
Abubakar got just 954 votes out of 8,000 in a vote to pick an opposition candidate. Three candidates are unlikely to garner significant votes.
Once formally decided, the winner will face President Goodluck Jonathan in elections scheduled for February 2015, seen as the closest fought since the end of military rule in 1999.
Jonathan won the ruling party ticket on Thursday in a no contest vote from nearly 3,000 delegates.
Buhari enjoys wide grassroots support, especially in the largely Muslim north, which has felt disenfranchised as power shifts to the more prosperous majority Christian south.
How Africa's biggest economy and leading energy producer conducts this election will be closely watched by investors and world powers. Past polls have been marred by ballot-box stuffing, bullying and in some cases completely fictitious results, although the 2011 one was judged the cleanest yet.
(Reporting by Tim Cocks, editing Jermey Gaunt)