The Abnormal Morphology of a Very Virulent Moroccan Isolate Belonging or Related to Puccinia hordei. R. E. Niks, Department of Plant Breeding (IvP), Agricultural University, P.O. Box 386, Wageningen, The Netherlands. R. G. Dekens, and A. van Ommeren. Department of Plant Breeding (IvP), Agricultural University, P.O. Box 386, Wageningen, The Netherlands. Plant Dis. 73:28-31. Accepted for publication 1 July 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0028.

An isolate of a “brown rust” fungus from barley collected in Morocco combined a rare virulence spectrum, viz., virulence to Pa3 and Pa7, and a relatively high aggressiveness on cv. Vada, known for its high level of partial resistance to Puccinia hordei. The morphology of the substomatal vesicle of this isolate differed remarkably from that of 17 isolates of P. hordei, including four Moroccan isolates with a more normal virulence spectrum and one Israelian isolate possessing virulence to Pa3 and Pa7. The telia contained one- and two-celled teleutospores and brown paraphyses, indicating that the isolate is at least closely related to P. hordei.