Reactions of Perennial Wild Species of Genus Glycine to Septoria glycines. S. M. Lim, Plant Pathologist and Professor, USDA-ARS and Department of Plant Pathology, University of Illinois, Urbana 61801. T. Hymowitz, Professor, Department of Agronomy, University of Illinois, Urbana 61801. Plant Dis. 71:891-893. Accepted for publication 29 May 1987. 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, 1987. DOI: 10.1094/PD-71-0891.

A total of 186 accessions from six perennial wild species of Glycine and a soybean cultivar (Williams) were evaluated for their reactions to Septoria glycines in the field after inoculation. Brown spot severity rated as the percentage of the total leaf area diseased ranged from 3 to 37.5% among the accessions at the R6 growth stage of Williams. Twenty-nine accessions with less than 3% severity were selected and evaluated in the greenhouse. Number and rate of formation of S. glycines pycnidia also were determined on infected leaves of these accessions. Four weeks after inoculation at V2–3 growth stages, brown spot severity ranged from 4 to 80% among the accessions, and the number of pycnidia on infected leaves after 7 days of incubation ranged from one to 75. Of 29 accessions, one of G. clandestina (PI 255745) and two of G. tabacina (PI 319697 and PI 321392) had less than 10% severity and fewer than five pycnidia per leaf (about 10 mm²), suggesting that these accessions can be useful as sources of resistance to S. glycines in intersubgeneric hybridizations with G. max.