VIEW ARTICLE

Resistance

Prehaustorial and Posthaustorial Resistance to Wheat Leaf Rust in Diploid Wheat Seedlings. R. E. Niks, Plant Breeding Department (IvP), Agricultural University, P.O. Box 386, 6700 AJ Wageningen, The Netherlands; R. G. Dekens, Plant Breeding Department (IvP), Agricultural University, P.O. Box 386, 6700 AJ Wageningen, The Netherlands. Phytopathology 81:847-851. Accepted for publication 31 January 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-847.

The histological reaction of 13 diploid wheat accessions (Triticum monococcum s.l.) to two isolates of wheat leaf rust (Puccinia recondita f. sp. tritici) was investigated and compared with the nonhost reactions to rye and barley leaf rust. The resistance of diploid wheat to wheat leaf rust ranged from almost completely prehaustorial without necrosis to almost completely posthaustorial with frequent necrosis. This variation depended on the diploid wheat accession rather than on the wheat leaf rust isolate. The nonhost reaction to rye leaf rust was predominantly prehaustorial. The nonhost reaction of the rye cultivar Rogo to barley leaf rust was predominantly posthaustorial with necrosis. In the diploid wheats the barley leaf rust formed haustoria rather frequently (with necrosis induction). The diploid wheat accessions with high prehaustorial resistance to wheat leaf rust may be valuable sources for nonhypersensitive (and perhaps durable) resistance in cultivated wheat to this fungus.