By Tom Ashby

Abuja - Nigeria's ruling party on Sunday chose a reclusive Muslim state governor, Umaru Yar'Adua, to be its candidate to succeed Olusegun Obasanjo as president of Africa's most populous nation in elections next year.

Yar'Adua, the 55-year-old governor of northern Katsina state, beat 11 other contestants for the People's Democratic Party (PDP) ticket to run in the April vote, which should mark the first fully democratic transition in Nigerian history.

"I want to congratulate my brother who will be my worthy successor," Obasanjo said after the vote by 4 000 delegates which began on Saturday and ended at dawn on Sunday.

Yar'Adua polled 3 024 votes with businessman Rochas Okorocha a distant second on 372.

Hours after the vote, Yar'Adua picked a governor from the oil producing Niger Delta, Goodluck Jonathan of southern Bayelsa state, as his running mate for vice president.

The atmosphere in the Eagle Square parade ground where the primaries took place was glum and most delegates left without waiting to hear the results or Yar'Adua's acceptance speech.

There was scant applause when the result was announced.

"He has a long way to go considering the gloomy faces of the delegates and the empty seats after voting," said Hamisu Shira, chairperson of the House Committee on Electoral Matters and PDP delegate.

Yar'Adua's candidacy rests almost exclusively on the support of Obasanjo. The former chemistry teacher is little known even among the political elite, having rarely left his remote northern state in seven years as governor.

Obasanjo persuaded influential state governors to back Yar'Adua, who suffers from a chronic kidney condition, with a mixture of inducements and threats of investigation by the fraud squad, insiders said.