Salinity Tolerance and Na+ Exclusion in Wheat: Variability, Genetics, Mapping Populations and QTL Analysis

A wide range of variability in both Na+ exclusion and salinity tolerance was shown in Triticum di-coccoides and the best performing genotype, from Getit, was identified for further study and for crossing. In bread wheat, plants BC6F1 from the cross Chinese Spring/line SQ1 showed less variability, but the line 1868 was identified as a potential source of tissue tolerance to salinity. Two Afghani durum landraces were identified among 179 screened, with approximately 50% lower Na+ accumulation in shoots. Genetic analysis of F-2 progenies between landraces and durum wheat showed clear segregation indicating on the single, major salinity tolerance gene in the landraces. Further genetic and molecular analysis of the candidate gene and its localization is in the progress. QTL analysis of two non-pedigree related mapping populations of bread wheat, Cranbrook x Halberd and Excalibur x Kukri, showed one QTL in each population on the same region of chromosome 7AS, independent of year or growing conditions (both supported hydroponics and field trials), and a novel gene is expected to be associated with this QTL.