Janata Dal United (JD-U) president Sharad Yadav on Monday stepped down from the post, ending his more than decade-long stint as party chief."At this point, (Bihar Chief Minister) Nitish Kumar is the most suitable for party president's post. He is most likely to be given the responsibility," a party source said.Yadav was the party chief for three consecutive terms ever since the JD-U was formed in 2003. "Sharad Yadav decided to step down as president as there is no provision for a fourth term for the post in party constitution," JD-U spokesman K.C. Tyagi told IANS.Party rules were earlier amended to enable Yadav to continue as JD-U chief as there was no provision for even a third term, Tyagi said.Tyagi refused to say who could be the next JD-U president.