QTLs analysis of some physiological traits in the Steptoe/Morex population of barley grown under saline and normal environments

The salinity stress after drought is the most important and the most common environmental stresses that limit crop production worldwide, including Iran. In order to determine the genomic regions of some physiological traits of "steptoe×morex" drived doubled haploid population of barley under normal and salinity stress conditions, an experiment was conducted at Research Farm, The experiment arranged in two randomized complete block design with two replication. Each plot included four rows with length of 3 m and 25 cm inter-rows distance. Triats such as chlorophyll content, chlorophyll fluorescence (Fo, Fv and Fv/Fm), relative water content (RWC), prolin content, water soluble carbohydrate (WSC) and cell membrane stability (CMS) were measured. QTL analysis was carried out using genetic linkage map derived from 327 molecular marker of RFLP and QTL cartographer software with composite interval mapping method. Combined analysis of varianc showed significant difference between the lines for all the studied traits. The maximum correlation was observed between Fo and Fv/Fm. In general, we found 43 QTLs (13, 16 and 14 QTLs for normal, salinity stress and mean of two conditions, respectively.) for the studied traits. Phenotypic variances that were explained by these QTLs changed from 9.06 to 30.28, respectively, for Fo (qFO 1m) and Fv/Fm (qFvFm 2.1m) in the mean of two conditions. LOD scores were ranged from 2.61 to 8.74, respectively, for the QTLs of chlorophyll content (qCHC1m) and Fv/Fm (qFvFm 2.1m) in mean of two conditions. QTL position 81.2 cM of chromosome 2H, controlling Fv/Fm, was quite stable. Therefore, it can be used in marker asisted selection.