Determination of QTLs Associated with Agronomic and Physiological Traits under Normal and Salinity Conditions in Barley

mapping the QTLs of agronomic and physiological traits, ۱۴۹ double haploid (DH) lines from a cross between an Australian cultivar, Clipper (salt susceptible), and an Algerian landrace, Sahara۳۷۷۱ (salt tolerant), were evaluated under natural saline (Yazd Station, ECsoil=۱۰-۱۲.۸ ds/m and ECwater= ۹-۱۰ ds/m) and normal (Karaj Station, ECsoil and ECwater ~۲-۲.۵ ds/m) environments. There were remarkable differences between parents and among the lines for studied traits, including days to heading, relative water content, chlorophyll content, plant height, spike length, days to maturity, biomass, grain yield, harvest index, grain number per spike, ۱۰۰۰ grain weight, Na+ and K+ contents and K+/Na+ ratio. QTL analysis was performed using the genetic linkage map consisted of ۵۱۷ molecular markers distributed evenly on all seven barley chromosomes spanning ۱۵۰۲ cM of barley genome based on composite interval mapping method. A total of ۷۲ QTLs for the measured traits were determined, from which ۴۰ QTLs were under normal and ۳۲ QTLs were under salinity stress conditions. The phenotypic variation explained by individual QTLs ranged from ۲.۷ to ۶۱.۸%. A major QTL related to biomass, grain number per spike, grain yield, plant height and ۱۰۰۰ grain weight was identified on chromosome ۲H in the vicinity of Vrs۱ marker locus. In addition, for plant height, biomass, grain number per spike and ۱۰۰۰ grain weight, some stable QTL(s) under both salinity and normal conditions were identified on that locus which considered as salinity related QTLs. These QTLs can be useful in breeding programs for improving salt tolerance using marker-assisted selection.

Keywords:

Agronomic Traits , Barley , QTLs , salinity