Seed Transmission and Yield Losses in Tropical Soybeans Infected by Soybean Mosaic Virus. Robert M. Goodman, Associate Professor, Department of Plant Pathology, and International Soybean Program (INTSOY), University of Illinois, Urbana 61801. James H. Oard, Assistant Agronomist, Department of Agronomy, and INTSOY, University of Illinois, Urbana 61801. Plant Dis. 64:913-914. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-913.

Ten tropical soybean accessions—five with low incidence of soybean mosaic virus (SMV) transmission through seeds (PI 86736 [Arisoy], PI 203406, PI 325779, PI 341256, and UFV-1), three with relatively high incidence of SMV seed transmission (PI 181698, PI 281901, and PI 340901), and two tropically adapted, widely used cultivars (Improved Pelican and Jupiter)—were planted at Isabela, Puerto Rico (18º N) in a randomized complete block design with split plots. Plants of each entry were or were not inoculated with an isolate of SMV not transmissible by aphids. Entries previously identified as nontransmitters of SMV through seed were found to transmit the virus but at very low incidence (≤ 0.2%). Improved Pelican also had a low incidence (0.23%) of virus transmission through seeds. Yield loss from SMV infection was linearly related to the logarithm of the percentage of seed transmission (r = 0.86). While the fundamental significance of this correlation is obscure, it is of considerable practical interest that soybean accessions are available that combine tolerance to SMV infection and low incidence of transmission through seeds.