Transgressive variation, commonly observed in interspecific progeny, offers the possibility of identifying superior offspring from crosses between two parents where neither represents the phenotypic extreme of interest. This possibility has immediate implications for quantitative trait loci (QTL) mapping for drought resistance in rice. Interspecific hybridization between Oryza sativa x O. glaberrima has proved to be an efficient way to generate superior rice cultivars adapted to the difficult rice-growing environments of Africa. To date, there has been little genetic analysis to determine which portions of these two genomes are complementary and which combinations of genes and QTL provide optimum performance in stress-prone environments. The power of QTL analysis is that it offers the ability to identify and ultimately clone genes underlying QTLs that are responsible for superior performance in the offspring of a biparental cross. QTLs associated with positive transgressive variation are of particular interest. Three O. glaberrima accessions (CG 14, 5486 TOG, 5980 TOG) were identified as drought tolerant in replicated trials at the Africa Rice Centre (WARDA) and have been used in crosses with O. sativa cvs. Moroberekan and WAB56-104, drought-tolerant tropical japonica varieties cultivated in Africa. Interspecific backcross populations are being developed for QTL mapping. Our objective is to generate interspecific segregants with enhanced drought tolerance for African farmers and to map QTLs associated with a variety of drought-related characters. Such information would provide an invaluable guide for future breeding efforts.