Since the 1980s, Ramularia leaf spot (RLS) is an emerging barley disease world-wide. The control of RLS is increasingly aggravated by a recent decline in fungicide efficacy and a lack of RLS-resistant cultivars. Furthermore, climate change increases drought periods in Europe, enhances variable weather conditions and thus will have an impact on severity of plant diseases. Hence, identification of RLS-resistant cultivars and understanding of disease progression under abiotic stress are important aims in integrated disease management under climate change. In the present study, we evaluated quantitative RLS resistance of 15 spring barley genotypes under drought, controlled irrigation and field conditions between 2016 and 2019 and monitored microclimatic conditions within the canopy. We identified genotypes that show robust quantitative resistance to RLS in different field environments. Our findings suggest that long-lasting drought periods create unfavourable conditions for the disease and supports that the extent and duration of leaf wetness is a key factor for RLS epidemics.

中文翻译：

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大麦的红斑病叶斑病高度依赖宿主基因型，并在田间持续干旱胁迫下得到抑制

自1980年代以来，横纹肌叶斑病（RLS）是世界范围内一种新兴的大麦病。由于杀真菌剂功效的最近下降和缺乏抗RLS的品种，RLS的控制日益恶化。此外，气候变化增加了欧洲的干旱时期，加剧了多变的天气条件，因此将对植物病害的严重性产生影响。因此，鉴定抗RLS品种并了解非生物胁迫下的疾病进展是气候变化下综合疾病管理的重要目标。在本研究中，我们评估了15种春季大麦基因型在2016年至2019年之间的干旱，控制灌溉和田间条件下的定量RLS抗性，并监测了冠层内的微气候条件。我们确定了在不同田间环境中对RLS表现出强大的定量抗性的基因型。我们的发现表明，长期干旱会为该病创造不利条件，并支持叶片潮湿的程度和持续时间是RLS流行的关键因素。