A Chromosome Segment Substitution Library of US Weedy Rice for Genetic Dissection of Complex Agronomic and Domestication Traits

Chromosome segment substitution lines (CSSLs) are a powerful genetic resource for quantitative trait loci (QTLs) mapping, map-based cloning, and analysis of gene interactions for important agronomic and domestication traits. Here we report development of a library of CSSLs of a straw hulled awnless US red rice accession ‘PSRR-1' with genome wide coverage in cultivated rice ‘Bengal’ background. Majority of CSSLs harbored single defined red rice segment with an average introgression segment of 2.8 % of the donor genome. Comparison of the QTL mapping results from both CSSL and RIL populations for a number of traits such as plant height, panicle length, flag leaf length, flag leaf width, grain length, grain width, thousand grain weight, seed dormancy, and seed shattering, indicated discovery of novel QTLs, which could be masked due to major QTLs or epistatic interactions of multiple QTLs in RIL population. The CSSL population represents a useful tool to discover the latent diversity in US red rice as well as for genetic dissection of many complex traits through cloning and characterization of the underlying genes.