Abstract:Cold stress is one of the major restraints for stable stand establishment at the early seedling stage of rice(Oryza sativa L.)for much of the production area.A recombinant inbred line population derived from a japonica/indica cross were assessed for cold tolerance at early seedling stage by the paper-roll tests at 10°C.Main-effect QTL for the trait were mapped via composite interval mapping using a linkage map with 198 marker loci.Four putative QTL for the trait were identified,which were mapped to chromosomes 1,3,7 and 11,respectively.Among these QTL,qSCT-11 showed a large additive effect on the trait,explaining 26%-30% of the phenotypic variation in the treatment of 13 d at 10℃ with a LOD of 16-19.This QTL was closely linked to SSR marker RM202 and its positive allele came from the parent Lemont.This allele would be useful for the improvement of rice cold tolerance via marker-assisted selection.