MUMBAI, Jan 20 - Prime Minister Narendra Modi's Bharatiya Janata Party (BJP) chose a little-known legislator from India's poorest state as the party's youngest president on Tuesday, a generational shift in the effort to retain young voters.

Nitin Nabin, 45, takes over from outgoing president J.P. Nadda, 65, months before key state elections, one of them in the eastern state of West Bengal, which the BJP has never won and is strongly focused on.