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Resistance

Mechanisms and Stability of Slow Stem Rusting Resistance in Avena sterilis. A. Sztejnberg, Department of Plant Pathology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel; I. Wahl, Department of Plant Pathology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel, Present address: Division of Mycology, Tel-Aviv University, Tel-Aviv, Israel. Phytopathology 66:74-80. Accepted for publication 10 July 1975. DOI: 10.1094/Phyto-66-74.

The study demonstrated that mechanisms controlling slow stem rusting in Avena sterilis involve restricted colonization of host tissue by mycelium, and decline in urediospore production per pustule both in seedling leaves and flag leaves of flowering plants. These factors functioned against all tested oat stem rust races, viz. 2, 8, 40, 41, and 72. The results support the concept that slow rusting is a form of general, race-nonspecific resistance. Races with “unnecessary” genes for virulence are as fit to colonize the host and to sporulate as are races with a narrow range of virulence. The slow stem rusting resistance in A. sterilis was effective in field trials in Puerto Rico, the USA, and Israel.