VIEW ARTICLE

Resistance

Control of Wheat Stem Rust by Low Receptivity to Infection Conditioned by a Single Dominant Gene. J. B. Rowell, Research plant pathologist, retired, Cereal Rust Laboratory, Agricultural Research Service, U.S. Department of Agriculture, University of Minnesota, St. Paul 55108; Phytopathology 72:297-299. Accepted for publication 8 June 1981. 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, 1982. DOI: 10.1094/Phyto-72-297.

The effectiveness of a single dominant gene for low receptivity to infection by Puccinia graminis f. sp. tritici in wheat (Triticum aestivum) cultivars Idaed 59 and W2691SrTt-1 was assessed for control of a moderately severe natural stem rust epidemic. This gene for low receptivity is either very closely linked to or identical to the gene SrTt-1 for specific resistance, for which the prevalent races in the epidemic were virulent. In the early stages of the epidemic, disease incidence and rate of disease increase were markedly less than those of the highly receptive Purdue 5481C1 and the intermediately receptive Baart and W2691. In the late stages of plant maturity, receptivity in leaf blades of Idaed 59 and W2691SrTt-1 increased, resulting in a rate of disease increase similar to that of the other cultivars, but terminal disease severities remained less. Rust caused significant losses in yield of W2691SrTt-1 and in kernel weight of Idaed 59 and W2691SrTt-1, but the percentage of loss was significantly less than that for the more receptive cultivars. Thus, the low receptivity of wheats with SrTt-1 to infection by races virulent to SrTt-1 offers useful protection against stem rust in areas of the United States where epidemics are light to moderate and infrequent.