Identification of gene loci controlling the Cd concentration of rice grain

摘要

A set of chromosome segment substitution lines (CSSLs) was used to identify the putative quantitative trait loci (QTLs) controlling cadmium (Cd) concentration in rice grain. The set consisted of a series of 39 lines and carried a single chromosome segment of 'Kasalath' iindica) in each line overlapping with a neighboring segment in a 'Koshihikari' (japonica) genetic background. The parents and CSSLs were grown in pots filled with Cd-polluted soil until grain filling. The Cd concentration in brown rice of Koshihikari was lower than that in Kasalath. The average grain Cd concentration in the CSSLs was intermediate between those of the parents. Seven CSSLs had significantly lower grain Cd concentrations than Koshihikari, and 4 had higher. On the basis of graphical genotypes of CSSLs, 3 putative chromosomal regions controlling grain Cd concentration were detected on chromosomes 3, 6, and 8. Each of the substitution lines was nearly isogenic to Koshihikari, which is the most popular rice cultivar in Japan: they carried more than 90% of the Koshihikari genetic background. Therefore, the development of a new Koshihikari with low grain Cd would be feasible in the near future.