Pathogenicity of Puccinia recondita f. sp. tritici in Morocco During 1985, 1988, 1990, and 1992. B. EZZAHIRI, Plant Pathologist, Departement de Phytopathologie, Institut Agronomique et Veterinaire Hassan II, Rabat, Morocco. S. DIOURI, Plant Pathologist, Departement de Phytopathologie, Institut Agronomique et Veterinaire Hassan II, Rabat, Morocco, and A. P. ROELFS, Research Plant Pathologist, Cereal Rust Laboratory, Agricultural Research Service, USDA, University of Minnesota, MN 55108. Plant Dis. 78:407-410. Accepted for publication 29 December 1993. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1994. DOI: 10.1094/PD-78-0407.

Surveys of pathogenic races of Puccinia recondita f. sp. tritici in Morocco in 1985, 1988, 1990, and 1992 indicated the presence of 12 unified numeration (UN) races. Virulence frequencies were high to Lr1, 2a, 3, 10, 16, and 17 and low to Lr3ka, 9, 24, and 26. The virulence frequency to Lr2a declined in 1990 and 1992. Isolates from durum wheats were generally less virulent than those from bread wheats to the designated Lr genes in a bread wheat background. The virulence diversity levels were higher in 1990 and 1992 than in 1985 and 1988. The populations with the highest phenotypic diversity were obtained from durum wheat cultivars and the susceptible bread wheat cultivar Siete Cerros. Durum wheat is often grown in marginal areas where the alternate host Anchusa italica occurs, while Siete Cerros is grown under irrigation in the south.