Sellas Tetteh has resigned as the coach of Rwanda after 18 months in charge.The Ghanaian quit the post in the wake of Saturday's 5-0 thrashing by Ivory Coast in the 2012 Africa Cup of Nations qualifier over the weekend."I have resigned as Amavubi head coach because of personal reasons," Tetteh said in a statement."I thank the Rwanda Football Federation, the Ministry of Youth, Sports and Culture and all for their support during my tenure."Tetteh, who is the only African coach to have won the the Under-20 World Cup, has resigned on the back of a poor showing in the 2012 Africa Cup of Nations qualifiers.He and his side were booed off the field following the defeat to the Elephants.The result left them bottom of Group H with three points from five matches and with no chance of qualifying for next year's tournament in Gabon and Equatorial Guinea.In his reign as Rwanda coach, Tetteh helped the Amavubi to qualify for the Africa Nations Championships (CHAN) in Sudan early this year but they failed to impress at the finals.He also guided them to the quarter finals of the Cecafa Challenge Cup tournament in Tanzania last year.Tetteh took over the Rwanda national team in February 2010 after helping Ghana to win Africa's first Under 20 World Cup in Egypt in 2009.