Science and Technology Branch, Agassiz Research and Development Center, Agriculture and Agri-Food Canada, Agassiz, British Columbia V0M 1A0, Canada.
Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Plant Dis. 2023 Mar;107(3):784-793. doi: 10.1094/PDIS-04-22-0931-RE. Epub 2023 Mar 21.
Phytophthora root rot and wilting complex (PRRW) of red raspberry, caused primarily by , is an economically important disease in British Columbia (BC) and in raspberry producing regions globally. Reliable, rapid, and efficient screening methods are lacking for evaluating germplasm for potential disease resistance in raspberry breeding programs as well as for screening pathogen isolates for virulence. The objective of this study was to compare various screening methods for efficiency and rapidity in inducing symptoms of disease to identify the most suitable approach. We compared several intact plant root inoculation (IPRI) assays, detached stem assays, and an intact plant stem inoculation (IPSI) assay. A virulent isolate of was inoculated in two commercial cultivars: 'Chemainus' (susceptible to PRRW) and 'Cascade Bounty' (moderately resistant to PRRW). For IPRI assays, days to first symptom development, plant wilt progression, and root assessment were recorded. For detached stem tissue and IPSI assays, days to first visible lesions and lesion size were assessed. Experiments were arranged in a completely randomized design with three replications in each experiment. Three IPRI assays produced reliable symptoms in both cultivars. Among the detached stem assays, a node inoculation method performed better than other methods. Detached stem assays are useful for rapid pathogenicity testing of , whereas IPRI assays are better for screening germplasm for disease resistance. Overall, this study identified several assays that can be used for conducting studies on pathogen phenotypic diversity (pathogenicity and virulence tests) and screening raspberry cultivars, germplasm, and breeding materials for response to PRRW.
覆盆子疫霉根腐和萎蔫复合病（PRRW），主要由 引起，是不列颠哥伦比亚省（BC）和全球覆盆子种植区的一种重要经济病害。在覆盆子育种计划中评估种质对潜在疾病抗性以及筛选病原体分离物的毒力时，缺乏可靠、快速和有效的筛选方法。本研究的目的是比较各种筛选方法在诱导疾病症状方面的效率和速度，以确定最合适的方法。我们比较了几种完整植物根系接种（IPRI）测定、离体茎测定和完整植物茎接种（IPSI）测定。接种了一种 的强毒分离株，在两个商业品种中：'Chemainus'（对 PRRW 敏感）和'Cascade Bounty'（对 PRRW 中度抗性）。对于 IPRI 测定，记录首次出现症状的天数、植物萎蔫进展和根系评估。对于离体茎组织和 IPSI 测定，记录首次出现可见病变的天数和病变大小。实验采用完全随机设计，每个实验重复三次。三种 IPRI 测定在两个品种中均产生可靠的症状。在离体茎测定中，节接种方法比其他方法表现更好。离体茎测定对于快速进行 的致病性测试很有用，而 IPRI 测定更适合筛选对 PRRW 具有抗性的种质。总的来说，这项研究确定了几种可以用于研究病原体表型多样性（致病性和毒力测试）以及筛选覆盆子品种、种质和对 PRRW 反应的育种材料的测定方法。
