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Resistance

The Relationship of the Sr6 Gene to Slow Rusting in Wheat. D. J. Cox, Former graduate student, Department of Plant Pathology, University of Minnesota, St. Paul, now graduate student, Department of Agronomy, Iowa State University, Ames 50011; R. D. Wilcoxson, professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 72:178-181. Accepted for publication 3 May 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-178.

In field studies, wheat lines that possessed the Sr6 gene generally developed stem rust more slowly than lines that did not. The Sr6 gene conditions slow rusting in conjunction with other minor genes as the temperature fluctuates about 24 C or when genes for virulence are present in the stem rust population. Heritability estimates indicated that the slow-rusting trait can be incorporated into a breeding population. Histological observations of the development of the stem rust pathogen in flag leaves of plants indicated that the greatest effect of the Sr6 gene was in its ability to suppress growth of the pathogen after penetration had been achieved.