Development and trait evaluation of chromosome single-segment substitution lines of O. meridionalis in the background of O. sativa

O. meridionalis is a wild species belonging to AA genome in the Oryza genus, which has a lot of beneficial genes for improvement of cultivated rice. In the present study, 99 chromosome single-segment substitution lines (SSSLs) were developed carrying donor segments of O. meridionalis in the genetic background of an indica cultivar, Huajingxian 74 (HJX74). The total lengths of the 99 substituted segments in the SSSLs were 1580.16 cM, with an average length of 15.11 cM per substituted segment, covering 873.94 cM and 54.98% of O.meridionalis genome. Phenotypic investigations of the SSSLs showed that three SSSLs had red pericarp, awn and showed seed shattering, respectively, indicating that these genes of O. meridionalis responsible for these traits have been transferred to the SSSLs. And wide variations were observed in seven quantitative traits including heading date and yield-related traits in 82 SSSLs.At P ≤ 0.001, 77 SSSLs showed significant differences compared with HJX74 in at least one trait either in the fall of 2014 or spring of 2015, and a total of 28 stable QTLs were detected in 24 SSSLs in both seasons. These results suggest that the SSSLs library of O. meridionalis developed in this study offers a good germplasm platform for the identification and transformation of beneficial genes of O. meridionalis, and facilitates the conservation of gene resources of O. meridionalis in vivo for long periods.