Jamaican athlete Bobby-Gaye Wilkins tested positive for a performance-enhancing substance during the IAAF World Indoor Championships last March in Doha, Qatar, the country's athletics governing body said on Friday. The test jeopardizes the legitimacy of Jamaica's third-place showing in the women's 4x400m relay behind the United States and Russia. Wilkins led off Clora Williams, Davita Prendergast and Novlene Williams-Mills in a Jamaican-record 3:28.46. It made Wilkins the sixth Jamaican track competitor to return a positive test in the past year. Yohan Blake, Lansford Spence, Sheri-Ann Brooks, Marvin Anderson and Allodin Fothergil returned positive tests from the Jamaica Championships last June and all received suspensions. 