Locating QTLs Controlling Agronomic Traits of “Steptoe×Morex” Derived Double Haploid Population of Barley under Drought Stress Conditions

In order to locate QTLs controlling some agronomic traits associated to drought stress and to determine their relationships with grain yield, an experiment was conducted at the Research Farm, College of Agriculture, University of Zabol in 2011. The experiment was arranged in two complete block designs with 3 replications. 72 barley double haploid lines including their parents (Steptoe×Morex) were planted under normal and drought stress conditions. Agronomic traits such as spike length, awn length, plant height, 1000 seed weight, number of tiller per plant, number of spike per plant, number of seed per spike and seed yield were measured. Simple statistics, combined analysis of variance and phenotypic correlation were calculated after averaging of data. QTL analysis was conducted separately by composite interval mapping (CIM) method for each trait in each condition and mean of two conditions. The main effect of genotype was highly significant for all the studied traits and tansgrasive segregation in both directions (positive and negative) was observed. Forty QTLs controlling different studied traits were identified. Phenotypic variance explained by these QTLs varies from 8.02 to 25.66%. The highest LOD scores were obtained for the spike length on 3H chromosome. High value of R2 and small confidence interval for these QTLs shown high linkage between markers and QTLs that can be used for breeding programs.