Association mapping of morpho-physiological traits in barley (Hordeum vulgare L.) under salinity stress

In this study molecular markers associated with morpho-physiological traits were identified using 14 AFLP primer combinations and 32 SSRs primer pairs across a cohort of 148 barley cultivars employing the association mapping approach. Phenotypic analysis was carried out using an alpha-lattice design with five incomplete blocks replicated twice under normal and salinity stress conditions (EC = 12 dS m-1) in two growing seasons. Population genetic structure was divided into two subpopulations (K = 2). In the present association panel, the mean of D´and r2, indicators for linkage disequilibrium (LD) were estimated at 0.25 and 0.02, respectively. The mixed linear model identified 194 significant marker-trait associations for nine studied traits under normal and salinity stress conditions. Several quantitative trait loci (QTLs) were stable for plant height, number of grains per spike, grain weight per spike, and leaf proline content traits under each of the environmental conditions, and termed stable QTLs. In addition, some stable QTLs were common to several traits and thereby enable barley breeder to undertake a concurrent selection of multiple traits to develop high-yielding cultivars. The identified markers could be useful in the implementation of marker-assisted selection in barley to improve the efficiency of selecting genotypes for salinity tolerance.