Timeline: Turkmenistan holds presidential election

(Reuters) - Turkmenistan holds a presidential election on Sunday which pits President Kurbanguly Berdymukhamedov against seven token challengers.

Here is a look at Turkmenistan over the past 20 years:

May 1992 - Turkmenistan adopts a new constitution proclaiming itself a democratic, secular state following the break up of the Soviet Union in 1991 and calls a presidential election for June. President Saparmurat Niyazov is re-elected in the state's first direct presidential election.

December 1999 - Parliament amends the constitution to allow Niyazov to hold the presidency for life.

August 2002 - Niyazov, officially known as Turkmenbashi, or Head of all Turkmen, proposes that January be renamed Turkmenbashi at a meeting of the People's Council, the country's highest consultative body.

-- Other months are to be given names such as "The Flag", "Independence" and "Rukhnama", the title of a quasi-religious spiritual guide written by Niyazov and published in 2001.

December 2006 - Niyazov dies from a heart attack on December 21.

February 2007 - Berdymukhamedov becomes president after elections, pledging to follow a path set by Niyazov and to respect existing energy contracts.

March 2007 - Berdymukhamedov says his main task is to raise living standards. Addressing the country's top legislative body, which he now heads, Berdymukhamedov pledges more pay for teachers and farmers as well as widespread Internet and mobile phone access.

September 2008 - Turkmenistan adopts a new constitution designed to improve the state's democratic credentials and assure investors of its economic openness.

-- Turkmenistan abolishes the Niyazov-era legislative body whose 2,500 delegates were hand-picked by the president, and transfers its powers to an elected 125-member parliament. It also announces elections to be held in December .

-- The new constitution vows to respect property rights and market economy principles.

December 2008 - Turkmens vote in a poll promoted by the government as a step to democracy, but criticized in the West for lack of choice - most candidates represented the Democratic Party led by Berdymukhamedov.

February 2009 - Amnesty International says Berdymukhamedov has failed to deliver on pledges to free up the Central Asian nation since being sworn in as president two years ago.

April 2009 - Russia, the main buyer of Turkmen gas, halts its imports after a pipeline explosion. The pipeline is repaired but the two sides cannot agree on new terms of sales as Russia's Gazprom needs less gas than in the past.

September 2009 - Berdymukhamedov tells visiting Russian President Dmitry Medvedev the two sides have managed to solve most technical problems and he expects a new deal to be agreed under a new pricing formula.

December 2009 - The gas pipeline TAGP (Trans Asian Gas Pipeline) is opened in Samandepe in Eastern Turkmenistan. The 1,833-km (1,139-mile) pipeline ends an era of Russian dominance over Central Asian energy exports and marks a new stage in Beijing's conquest of untapped riches in a vast region wedged between China, Russia, Iran and Afghanistan.

July 2010 - The president announces plans to permit the creation of private newspapers.

November 2010 - Turkmenistan says it has won support from its Caspian neighbors to lay a pipeline under the sea and become a major gas supplier to Europe, boosting plans for the EU-backed Nabucco project. The country will have up to 40 billion cubic meters of gas spare to supply to Europe.

February 2012 - Presidential election.

(Reporting by David Cutler, London Editorial Reference Unit)