Abstract:Objective To evaluate effects of Cd stress on seed germination and growth of seminal root and shoot in chromosome single-segment substitution lines (SSSLs) of Oryza glumaepatula after seed germination, screen for Cd-tolerant SSSLs, and identify QTLs related to Cd-tolerant characters in bud.Method The seed germination test was carried out using six varieties at CdCl2 concentrations of 0, 30, 50, 100, 500 μmol·L-1, and the proper treatment of CdCl2 concentration and the related character indexes to evaluate CdCl2 tolerance of SSSLs were determined. The lengths of seminal roots and shoots of experimental SSSLs were analyzed to screen for SSSLs with strong tolerance to CdCl2 at P=0.01 level and identify QTLs related to Cd-tolerant characters.Result At the concentrations of 0, 30, 50, and 100 μmol·L-1 CdCl2, the seed germination rates of six varieties were distributed between 91%~95%, which were insignificant among different CdCl2 concentrations. However, the growth of seminal roots and shoots were significantly inhibited by CdCl2, and the significant differences were observed for the tolerance to CdCl2 among different varieties. Using relative root length and relative shoot length on the 7th day after germination as tolerance indexes, at the concentrations of 50 and 100 μmol·L-1, five relative root length QTLs including qRRL1-1, qRRL2-1, qRRL3-1, qRRL3-2 and qRRL6-1 were identified in eight SSSLs at P=0.01 level, the phenotypic contribution rates of additive effects ranged from 31.18% to 100.59%. Three relative shoot length QTLs including qRSL1-1, qRSL1-2, and qRSL2-1 were identified in five SSSLs, the phenotypic contribution rates of additive effects were 7.43%~18.95%.Conclusion SSSLs of O. glumaepatula carry Cd-tolerant QTLs at the germination period, which will be useful for exploring beneficial Cd-tolerant genes in rice.