A backcross was made to develop the mapping population EM93-1//EM93-1/SS18-2 (BC1). SS18-2 is a wild-like, indica type of weedy rice originating from Thailand that has a red pericarp/testa color. SS18-2 seeds have mainly hull-imposed dormancy and heritability for this trait ranged from 0.64 to 0.95 in seeds after-ripened for 0 to 60 days. EM93-1 is a nondormant, short growth duration, indica type of breeding line. A weedy rice framework genetic map was constructed on the basis of a primary segregating population of 156 BC1 individuals. The linkage map consists of 151 SSR markers distributed along 12 chromosomes and a red pericarp/testa color gene Rc. The average intermarker distance was 13.5 cM and the total distance was 1900 cM.