Substitution mapping of quantitative trait loci (QTLs) for yield and its components by comparing overlapping segments among chromosome segment substitution lines (CSSLs). QTLs in the Koshihikari (A) and Takanari (B) backgrounds. Chromosome numbers are indicated above each physical map. Marker names are located to the left of each chromosome. Colored arrows denote putative QTLs for yield and its components. Upward and downward arrowheads indicate that the trait value was increased by the Takanari or Koshihikari allele, respectively.