Low cadmium (Cd) accumulation in brown rice (Oryza sativa) is an important trait for food safety. An effective way to reduce Cd accumulation in the grain is to control Cd transfer from the roots to the shoots. In the present study, we characterized high-Cd accumulating accession (Nepal 555, indica) and performed QTL analysis for shoot Cd accumulation in a F2 population derived from a cross with a low-Cd accumulating accession (Shwe War, japonica). Physiological study showed that Nepal 555 possesses higher ability for Cd translocation from the roots to shoots, while there was no difference in Cd uptake from external solution between two accessions. Two major QTLs were detected on chromosome 11 and 6. These QTLs explained 47% and 12%, respectively, of phyenotypic variations of Cd accumulation. Furthermore, an interaction between the QTLs on the chromosome 6 and 11 was found.
