Field-Based Assessment of Slow Rusting Resistance Against Yellow Rust in Irrigated Barley Promising Lines

Yellow rust (stripe rust) caused by Puccinia striiformis f. sp. hordei is an important disease that threatens barley production in some areas of the world. Host resistance is the most economical strategy to manage barley stripe rust, and slow rusting resistance, a type of quantitative resistance, has been reported to be more durable than other type of resistance. Slow rusting parameters including final rust severity (FRS), apparent infection rate (r), relative area under disease progress curve (rAUDPC), and coefficient of infection (CI) were evaluated in a set of 41 barley promising lines together with susceptible control in 2016 and 2017 cropping seasons. This study was conducted in field plots at Ardabil Agricultural Research Station, Ardabil, Iran, under artificial infection conditions of race populations of Ardabil. Seedling reaction was also evaluated under field conditions. Results of evaluation for resistance parameters showed that lines; EDC-87-3, EC-90-4, EM-88-2, EM-88-5, EM-89-19 and susceptible check had the highest values of FRS, CI, r and rAUDPC, therefore, were considered as susceptible. Ten lines were resistant at seedling and adult plant stages, seven lines showed resistance at seedling, but had moderate reactions at adult plant stage. Thirteen lines (2, 5, 8, 10, 12, 14, 15, 19, 23, 29, 31, 38 and 39) were susceptible at the seedling stage and had intermediate (MR, M or MS) reactions at adult plant stage. Therefore, these lines with low level of different measured parameters were assumed to have gene(s) for varying degrees of slow rusting resistance or high temperature adult plant resistance (HTAPR). The remaining lines had low level of slow rusting resistance. Cluster analysis based on adult plant resistance parameters and seedling infection types revealed different groups which indicated considerable variation for different level of resistance among the barley promising lines examined in this study.