Soybean Mosaic Virus: Effects of Primary Disease Incidence on Yield and Seed Quality. J. H. Hill, Department of Plant Pathology, Seed and Weed Sciences, Iowa State University, Ames 50011. T. B. Bailey, H. I. Benner, H. Tachibana, and D. P. Durand. Department of Statistics, Department of Plant Pathology, Seed and Weed Sciences, Research Plant Pathologist, USDA, ARS, and Department of Microbiology, Iowa State University, Ames 50011. Plant Dis. 71:237-239. Accepted for publication 30 September 1986. 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-71-0237.

Various percentages of seedling plants of the soybean cultivar Amsoy 71 were inoculated in a random pattern with soybean mosaic virus (SMV). Seeds harvested from plots, graded for seed-coat mottling, and analyzed for SMV antigen by solid-phase radioimmunoassay showed that levels of virus antigen were positively correlated with disease incidence. Yield reductions were similar in plots where 30 or 50% of the plants were inoculated. Experiments in which seed with known antigen levels was used to plant plots showed that antigen levels from seeds harvested from such plots either decreased or increased, depending on the year. It is probable that such results are dependent on the degree of secondary spread and time of inoculation.