John Garang, who led Sudan’s southern rebels for two decades before making peace and joining the government he fought, died in a helicopter crash, sparking riots and fears for the country’s hard-won stability.A key figure in a January peace deal hailed as a rare success story for Africa, Garang had been in talks with Ugandan President Yoweri Museveni, leaving Uganda by helicopter late on Saturday. Khartoum said on Monday that he died over the weekend after the Ugandan presidential helicopter he was travelling in went down in bad weather.Six of Garang’s companions and a crew of seven also died in the crash near the Sudan-Uganda border, Khartoum said, although a member of the southern Sudan leadership council said 17 bodies were recovered.Members of Garang’s southern Sudan People’s Liberation Movement (SPLM) and the government in Khartoum—bitter enemies during the 21-year conflict—both vowed to maintain the peace agreement Garang helped create.Sudan’s President Omar Hassan al-Bashir expressed confidence the power-sharing peace accord would remain intact. ‘‘We are confident that the peace agreement will proceed as it was planned,’’ he said in a televised statement.Garang had taken the Sudanese Vice Presidency just weeks before amid a tumultuous popular welcome in Khartoum. Later on Monday, the SPLM named General Salva Kiir as Garang’s successor. ‘‘The SPLM leadership unanimously affirmed General Salva Kiir Mayardit as the chairman of the SPLM and commander in chief of SPLA,” SPLM’s senior official Pagan Amun said. ‘‘ He is therefore the nominee to the position of the first Vice President of the Republic of Sudan and the President of the government of South Sudan.’’ —Reuters