BISHKEK (Reuters) - Kyrgyzstan will choose its next president from a list of 20 candidates in an election next month that could expose divisions between the north and south of the volatile Central Asian state. Official campaigning began on Monday after the Central Election Commission named its final list of candidates for president of the strategic country of 5.5 million people, which hosts both US and Russian military air bases. The Oct. 30 vote, which some analysts say will need a second round, will pit current Prime Minister Almazbek Atambayev against heavyweight rivals from the south of the country, where central government's grip on power is tenuous.