QTL Mapping of Salt Tolerance Traits with Different Effects at the Seedling Stage of Bread Wheat

We evaluated salt tolerance in 319 recombinant inbred lines derived from a cross between Roshan and Falat (seri82) in bread wheat (Triticum aestivum L.). This study identified quantitative trait lci (QTLs) with additive (a) and additive x additive (aa) epistatic effects, and characterized their salt treatment interactions (at and aat) at the seedling stage. Using a genetic map of 730 DArT and SSR markers, we identified 65 additive QTLs governing 13 traits using the QTL Cartographer program to assess single-treatment phenotypic values. We further identified 13 additive and 14 epistatic QTLs for 10 traits with the QTLNetwork program using multitreatment phenotypic values. Our results show that four of the additive and seven of the epistatic QTLs exhibited an effect on the response to salt treatment. Morphological traits had less effect on treatment than physiological traits did. Of the three additive QTLs found to affect shoot Na+ concentration, two colocalized with loci governing shoot fresh or dry weight (1B-2 and 3B-1). Thirteen pairs of QTLs across five chromosomal groups were detected at homologous positions in the A, B, and D genomes, indicative of synteny.