title: Detection of QTLs to reduce cadmium content in rice grains using LAC23/Koshihikari chromosome segment substitution lines.
abstract: To advance the identification of quantitative trait loci (QTLs) to reduce Cd content in rice (Oryza sativa L.) grains and breed low-Cd cultivars, we developed a novel population consisting of 46 chromosome segment substitution lines (CSSLs) in which donor segments of LAC23, a cultivar reported to have a low grain Cd content, were substituted into the Koshihikari genetic background. The parental cultivars and 32 CSSLs (the minimum set required for whole-genome coverage) were grown in two fields with different natural levels of soil Cd. QTL mapping by single-marker analysis using ANOVA indicated that eight chromosomal regions were associated with grain Cd content and detected a major QTL (qlGCd3) with a high F-test value in both fields (F = 9.19 and 5.60) on the long arm of chromosome 3. The LAC23 allele at qlGCd3 was associated with reduced grain Cd levels and appeared to reduce Cd transport from the shoots to the grains. Fine substitution mapping delimited qlGCd3 to a 3.5-Mbp region. Our results suggest that the low-Cd trait of LAC23 is controlled by multiple QTLs, and qlGCd3 is a promising candidate QTL to reduce the Cd level of rice grain.
authors.affiliation: Soil Environment Division, National Institute for Agro-Environmental Sciences , 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 , Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Abe
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Nonoue
authors.forename: Nozomi
authors.initials: N
authors.lastname: Ono
authors.forename: Motoyasu
authors.initials: M
authors.lastname: Omoteno
authors.forename: Masato
authors.initials: M
authors.lastname: Kuramata
authors.forename: Shuichi
authors.initials: S
authors.lastname: Fukuoka
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
authors.forename: Satoru
authors.initials: S
authors.lastname: Ishikawa
keywords: chromosome segment substitution lines (CSSLs); low cadmium (Cd); paddy field; quantitative trait locus (QTL); rice grain