Gossypium L. is a genus of about 48 species that occurs in relatively arid regions of Africa, Arabia, Australia, and North and South America (Fryxell, 1992). Of the 43 known wild diploid Gossypium species, 18 are found in Australia. All Australian species belong to the subgenus Sturtia which is divided into three sections, Sturtia, Hibiscoidea and Grandicalyx. The 5 Australian arid zone species possess terpenoid glands in their green tissue but their seeds have rudimentary glands in the embryo. This characteristic is unique in the genus and four of the Australian species, G. sturtianum, G. australe and G. bickii have been the focus of research to transfer this trait into Upland and/or Old World cotton to achieve insect resistance while maintaining the embryo free of toxic substances that lower its feed or food value (Craven et al., 1995). Gossypium bickii was placed in the C genome before Edwards and Mirza (1979) gave it a new genomic designation "G" on the basis of differences in chromosome size and karyotype compared to other Australian Gossypium species. Morphologically, G. bickii is closely related to the other two Australian species (G. australe and G. nelsonii) of section Hibiscoidea (Fryxell, 1965, 1979; Stewart et al., 1987). Partially fertile hybrids among G. bickii, G. australe and G. nelsonii have been reported and recommendation for the inclusion of these three species in a single genomic group have been made (Stewart and McCombie 1991). In view of the distinctive evolutionary history of G. bickii (Wendel et al., 1991), we wished to observe its genomic affinity with other Australian species. Gossypium australe and G. nelsonii were included because of their taxonomic placement (section Hibiscoidea) and morphological similarities. Gossypium sturtianum, which belongs to section Sturtia, was incorporated because of its cytoplasmic similarity with G. bickii (Wendel et al., 1991) and G. nandewarense was included because of questions concerning its distinction from G. sturtianum (Fryxell, 1992; Craven et al., 1995). Two species from the Australian section Grandicalyx, G. enthyle and G. anapoides (Stewart et al., 1997) were incorporated in the study as representatives of section Grandicalyx, and G. triphyllum was taken into consideration because of its previous inclusion in section Hibiscoidea by Fryxell (1979; 1984) based on morphological similarities. Gossypium longicalyx was used as an out group.