Development of chromosome segment substitution lines derived from indica rice donor cultivars DV85 and ARC10313 in the genetic background of japonica cultivar Taichung 65

We have developed two sets of chromosome segment substitution lines (CSSLs) of cultivated rice (Oryza sativa) carrying donor segments from indica cultivars DV85 and ARC10313. The lines in each set contain chromosomal segments that cover most of the donor genome in a uniform genetic background (ssp. japonica cv. Taichung 65). The starting materials were several recombinant inbred lines derived from the crosses Taichung 65 x DV85 and Taichung 65 x ARC10313. The CSSLs were generated by repeated backcrossing to Taichung 65 (pollen parent), with marker-assisted selection applied at several marker loci. The CSSLs of DV85 (TD-CSSLs) comprise 45 lines that cover 76.6% of the DV85 genome, and the CSSLs of ARC10313 (TA-CSSLs) comprise 44 lines that cover 74.4% of the ARC10313 genome. We investigated the genetic control of days-to-heading in both sets of CSSLs and demonstrated the genetic contribution of several chromosome regions. These CSSLs provide a valuable tool for rice germplasm enhancement, and we expect them to reveal the genetic basis of traits specific to the donor cultivars.