Chromosome segment substitution lines (CSSLs) are useful for the precise mapping of quantitative trait loci (QTLs) and dissection of the genetic basis of complex traits. In this study, two whole-genome sequenced rice cultivars, the japonica Nipponbare and indica 9311 were used as recipient and donor, respectively. A population with 57 CSSLs was developed after crossing and back-crossing assisted by molecular markers, and genotypes were identified using a high-throughput resequencing strategy. Detailed graphical genotypes of 38 lines were constructed based on resequencing data. These CSSLs had a total of 95 substituted segments derived from indica 9311, with an average of about 2.5 segments per CSSL and eight segments per chromosome, and covered about 87.4% of the rice whole genome. A multiple linear regression QTL analysis mapped four QTLs for 1000-grain weight. The largest-effect QTL was located in a region on chromosome 5 that contained a cloned major QTL GW5/qSW5 for grain size in rice. These CSSLs with a background of Nipponbare may provide powerful tools for future whole-genome discovery and functional study of essential genes/QTLs in rice, and offer ideal materials and foundations for japonica breeding.
Copyright © 2011. Published by Elsevier Ltd.