Abstract: The purple stigmas,which were caused by the metabolism of anthocyanins,were normal among all AA genome wild rice species including Oryza longistaminata.To study the purple stigmas in O.longistaminata,backcrossing was applied between the donor parent O.longistaminata with achromatic stigmas and recurrent parent RD23 with purple stigmas,and after embryo rescue and consecutive backcrossing three BC6F1 populations that showed character segregation in stigma color were finally got.In all BC6F1 populations,the segregation raito of purple stigma to achromatic stigma was 1: 1,suggesting that the purple stigma was controlled by a pair of dominant allele.An analysis using microsatellite markers (SSR) demonstrated that the target gene located on the No.6 chromosome which was 2.5 cM,0 cMand 4.4 cMfrom RM253,RM111 and RM6917,respectively.After comparing its position and effect to those published data,this gene might be allelic to Ps-4(t),which was identified from O.sativa.