Genomic DNA was extracted from leaf tissues using the Sarkosyl method (Yuan et al. 2012 (link)), measured using ND-1000 spectrophotometry (Thermo Fisher Scientific, Wilmington, DE, USA), and normalized to 50 ng µl−1. A total of 93 F2 plants from POP371 and the two parental lines were genotyped using an Illumina VeraCode custom assay (del Blanco et al. 2014 (link)). This assay includes 384 single nucleotide polymorphisms (SNP) selected from the Illumina GoldenGate BOPA1 and BOPA2 assays for even coverage of the barley genome (Close et al. 2009 (link)). A genetic linkage map was created using the maximum likelihood mapping algorithm with the Kosambi function as implemented in JoinMap 4.0 (Kyazma B.V., Wageningen, Netherlands). The Windows QTL Cartographer V2.5 (Wang et al. 2012 ) was used to identify QTL for Pst resistance using composite interval mapping (window size: 10 cM; walk speed: 1 cM). Significance thresholds were established using 1000 permutation tests. QTL with a logarithm of odds (LOD) score of three or more were considered significant.
The degree of dominance was calculated using the formula: D = (2X2 − X1 − X3)/(X1 − X3) (Falconer 1964 ), where X1,X2 and X3 are the infection types scores of the plants homozygous for the markers flanking the Rps6 resistant allele, the heterozygous, and the plants homozygous for the markers flanking the susceptible allele, respectively.
The degree of dominance was calculated using the formula: D = (2X2 − X1 − X3)/(X1 − X3) (Falconer 1964 ), where X1,X2 and X3 are the infection types scores of the plants homozygous for the markers flanking the Rps6 resistant allele, the heterozygous, and the plants homozygous for the markers flanking the susceptible allele, respectively.