By Margarita Antidze
TBILISI (Reuters) - Georgian Prime Minister Bidzina Ivanishvili on Saturday named a pro-Western ally as the ruling party candidate for October's presidential election, in which incumbent Mikheil Saakashvili is barred from running.
Ivanishvili's Georgian Dream coalition won control of parliament in October last year, defeating the party of Saakashvili, a leader of the 2003 Rose Revolution protest movement, and is favorite in opinion polls to take the presidency.
Friction between Ivanishvili and Saakashvili has threatened stability in the former Soviet republic, a conduit for pipelines pumping Caspian Sea energy westward and a platform for geopolitical rivalry between the United States and Russia. Georgia fought a brief war with Russia in 2008.
Constitutional changes that take effect after the new president is inaugurated will increase the powers of the prime minister at the expense of the president.
Ivanishvili said Georgian Dream had chosen Georgy Margvelashvili, an academic who is Education Minister and a vice-premier, as its presidential candidate.
Margvelashvili, 43, has been a vocal critic of Saakashvili. He was rector of the Tbilisi-based Georgian Institute of Public Affairs (GIPA) from 2000-2006 and again in 2010-2012.
"We did not even discuss any other candidates ... No one was against his candidacy," Ivanishvili told reporters.
The billionaire tycoon-turned-prime minister had previously said of Margvelashvili: "Whenever I come across difficulties I always call Georgy and ask him (for advice). I have two or three such people with whom I can sit down and talk about any issue and any problem."
Saakashvili's United National Movement party has yet to name a candidate in the presidential vote. Saakashvili has served the constitutional limit of two terms.
(Reporting by Margarita Antidze; Editing by Steve Gutterman and Janet Lawrence)