Douiyssi A, Rasmusson D C, Roelfs A P
Plant Breeder, INRA Settat, Morocco.
Plant Breeder, Department of Agronomy and Plant Genetics, University of Minnesota.
Plant Dis. 1998 Mar;82(3):316-321. doi: 10.1094/PDIS.1998.82.3.316.
Net blotch, caused by Pyrenophora teres, is among the most damaging foliar diseases of barley worldwide. A knowledge of the reaction of local cultivars, putative resistant lines, and variability in the net blotch pathogen is necessary to develop a successful resistance breeding program. Disease responses of 38 barley lines to 15 P. teres isolates were studied at the seedling and adult plant stages in the glasshouse, and field responses to net blotch were evaluated at three Moroccan locations. No tested barley was resistant to all isolates, and resistance was apparently of the specific type. Pathogenic variability was great, as none of the 15 isolates were identical. For each isolate tested, a specific high level of resistance was found in one or more host lines. Seedling and adults plants often differed in response to the same isolate. Adult plant resistance was commonly observed in response to isolate I-1, and seedling resistance was more common to isolate I-14. Adult plant resistance of nine lines was undetected in seedling evaluations using isolate I-1. The seedling glasshouse and field responses of the barley lines varied considerably, limiting the value of seedling testing for resistance. Field reactions of resistant and moderately resistant were consistent across the three locations for the lines Heartland, Minn 7, CI 2333, and CI 2549. The variability observed in P. teres and failure to find lines with resistance to all isolates suggests that breeding for resistance should emphasize pyramiding of resistance genes.
网斑病由柄锈菌引起，是全球范围内对大麦危害最大的叶部病害之一。了解当地品种、假定的抗性品系以及网斑病病原菌的变异性，对于制定成功的抗性育种计划至关重要。在温室中研究了38个大麦品系对15个柄锈菌分离株在幼苗期和成株期的病害反应，并在摩洛哥的三个地点评估了对网斑病的田间反应。没有一个测试大麦对所有分离株都具有抗性，而且抗性显然是特异性的。致病变异性很大，因为15个分离株没有一个是相同的。对于每个测试的分离株，在一个或多个寄主品系中发现了特定的高抗性水平。幼苗期和成株期对同一分离株的反应常常不同。对分离株I-1的反应通常观察到成株期抗性，而对分离株I-14的反应则更常见幼苗期抗性。在使用分离株I-1进行的幼苗评估中，未检测到9个品系的成株期抗性。大麦品系在幼苗温室和田间的反应差异很大，限制了幼苗抗性测试的价值。对于Heartland、Minn 7、CI 2333和CI 2549品系，在三个地点的抗性和中度抗性田间反应是一致的。在柄锈菌中观察到的变异性以及未能找到对所有分离株都具有抗性的品系表明，抗性育种应强调抗性基因的聚合。
