QTL Analysis for Sodium and Potassium Concentration and Potassium to Sodium Ratio in Wheat Under Salt-Stress Condition

So far, many quantitative trait loci (QTLs) have been detected for yield and its components in wheat under normal conditions. In order to identify QTLs associated with concentrations of sodium and potassium in bread wheat under salt stress conditions, a population consisted of 186 recombinant inbred lines from a cross between Roshan ×SuperHead#2 were evaluated. Salinity treatments were performed using a hydroponic system in a greenhouse. Normal conditions (10 mM NaCl) and salinity (150 mM NaCl) were considered and stress was conducted in stages. The molecular genetic map of the population consisted of 23 simple sequence repeat (SSR) and 428 diversity arrays technology (DArT) markers. Three QTLs for each of sodium and potassium concentration traits and a QTL for potassium to sodium ratio were detected on chromosomes 4A, 2B, 3B, 7B and 2D using composite interval mapping approach. The QNa.abrii-3B, with a LOD score of 5.9, explained 8.3 % of the phenotypic variation for sodium concentration under salt stress conditions and gwm247 marker showed a strong linkage with this QTL. In addition, two novel QTLs for sodium concentration were detected on chromosomes 2B and 2D and QNa.abrii-2D explained 9.2 % of the phenotypic variation for this trait under salt stress conditions. Proceed with future researches, there is probability of identifying QNa.abrii-2B and QNa.abrii-2D as two homoeologous group in wheat, beside Nax1 gene.