BULAWAYO, July 18 (Reuters) - - Zimbabwe beat Afghanistan by six wickets in the first one-day international in Bulawayo on Friday to take a 1-0 lead in the four-match series. Scores: Afghanistan 223 for nine in 50 overs (Samiullah Shenwari 65 not out, Mohammad Nabi 54; T. Chatara 2/37) Zimbabwe 227 for four in 45.2 overs (S. Williams 70) (Compiled by Nick Said, editing by Tony Goodson)