Identification of QTLs for salt tolerance at germination and seedling stage of Sorghum bicolor L. Moench

Abstract

Salt stress is a major limitation for crop production in saline soil. For investigating genetic mechanism of salt tolerance at germination and seedling stage, and improving salt tolerance of sorghum, 181 recombinant inbred lines derived from Shihong137 and L-Tian were used in this study. Quantitative trait loci (QTLs) for three traits at germination stage and nine traits at seedling stage were analyzed. 12 and 29 QTLs were identified at germination and seedling stage, respectively. Only qGP7-1 for germination percentage was found consistently under control and 2.0 % NaCl stress. Other QTLs detected under salt stress were salt specific expression. Six major QTLs were identified, and positive effects were all from Shihong137 except that of qRL10-2. Five chromosome regions controlling more than one trait simultaneously were found under salt stress. The results demonstrated that salt tolerance at germination and seedling stage of sorghum was a complex quantitative trait and controlled by multiple genes. However, six major QTLs and five chromosome regions played crucial role in salt tolerance of sorghum, which could be applied in marker assisted selection and in further investigation for salt tolerance.