VIEW ARTICLE

Effects of Soybean Mosaic Virus and/or Bean Pod Mottle Virus Infection on Soybean Nodulation. J. C. Tu, Postdoctoral Research Associate, Department of Botany and Plant Pathology, Iowa State University, Ames 50010, Present address of senior author: Plant Pathology Department, University of Alberta, Edmonton, Alberta, Canada; R. E. Ford(2), and S. S. Quiniones(3). (2)Professor, Department of Botany and Plant Pathology, Iowa State University, Ames 50010; (3)Postdoctoral Research Associate, Department of Botany and Plant Pathology, Iowa State University, Ames 50010. Phytopathology 60:518-523. Accepted for publication 22 October 1969. DOI: 10.1094/Phyto-60-518.

Nodulation was studied in soybeans infected with soybean mosaic virus (SMV), with bean pod mottle virus (BPMV), or with both viruses. Nodule differences were marked between soybean varieties, but were small within soybean varieties infected with different SMV isolates. Number, size, and wt of nodules were reduced by SMV infection, and the earlier the infection, the greater the reduction. Maximum reduction (81%) occurred when Bansei soybeans were inoculated 2 weeks after sowing, but none occurred 9 weeks or later. Marked decreases in nodule numbers often resulted in an increase in nodule sizes in virus-infected plants. A mixed infection of soybeans by SMV and BPMV reduced nodules more than single infections. Frequent fertilizer applications reduced nodule production in both healthy and SMV-infected plants. Decreases in plant fresh wt in SMV-infected soybeans has been attributed primarily to decreased photosynthesis and increased respiration. Reduced nodulation may also be an important factor.