Leaf scald caused by Rhynchosporium secalis, is a serious disease of barley (Hordeum vulgare L.) in Tunisia. A doubled-haploid barley population, from a cross between the two-rowed ‘Roho’ and the six-rowed ‘L90’ cultivars, was evaluated for its reaction to scald under natural infection in replicated field trials for two years. Phenotypic variation among doubled-haploid lines was significant for disease reaction in both environments (cropping seasons) and genotype × environment interaction was also significant. Heritability estimates were high in both seasons and significant correlation was noted between scald reactions recorded in the two seasons. Segregation of 34 single sequence repeat markers was used for quantitative trait loci mapping. Single-marker analysis was applied for individual and for combined environments to determine the effect of each molecular marker on scald resistance. In total, six QTLs with additive effects were mapped on chromosomes 2H, 3H, 4H, 6H and 7H which explained from 4.4 to 11.7% of the phenotypic variance. Among these, only QTLs linked to WMS6 (4H) and to HVM31 (6H) showed significant QTL × environment interactions. QTLs associated to HVM36 (2H) and to Bmag0571 (7H) were the most significant for scald resistance and the most insensitive to the environment. Another stable QTL was identified, for the first time, in the vicinity of the Vrs1 locus on the 2H chromosome. For this QTL, the two-rowed parental allele reduced disease severity. These chromosomal regions that affect scald resistance independently of the environment would be of great interest in marker-assisted selection.

中文翻译：

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大麦二行×六行杂交抗烫伤QTL和QTL×环境互作检测

由Rhynchosporium secalis 引起的烫伤是突尼斯大麦(Hordeum vulgare L.) 的严重病害。在两年的重复田间试验中，对来自两行“Roho”和六行“L90”品种杂交的双单倍体大麦种群进行了评估，评估其对自然感染下烫伤的反应。双单倍体系之间的表型变异对两种环境（种植季节）中的疾病反应都很显着，基因型×环境相互作用也很显着。两个季节的遗传力估计值都很高，并且在两个季节记录的烫伤反应之间发现了显着的相关性。34 个单序列重复标记的分离用于数量性状基因座作图。单标记分析适用于个体和组合环境，以确定每个分子标记对抗烫伤性的影响。总共有六个具有累加效应的 QTL 被定位在染色体 2H、3H、4H、6H 和 7H 上，这解释了 4.4% 到 11.7% 的表型变异。其中，只有与 WMS6 (4H) 和 HVM31 (6H) 相关的 QTL 显示出显着的 QTL × 环境相互作用。与 HVM36 (2H) 和 Bmag0571 (7H) 相关的 QTL 对烫伤抗性最重要，对环境最不敏感。在 2H 染色体上的 Vrs1 基因座附近首次发现了另一个稳定的 QTL。对于这个 QTL，双排亲本等位基因降低了疾病的严重程度。