Identification of Field Tolerance to Bean Pod Mottle and Soybean Mosaic Viruses in Soybean

Development of a method to identify field tolerance to bean pod mottle and soybean mosaic viruses (BPMV and SMV) in soybean [Glycine max (L.) Merr.] allowed evaluation of 33 soybean accessions for field response to BPMV and SMV. Based on measurement of parameters that included relative level of virus antigen in seed and mottling of soybean seed coats, three accessions showed tolerance to SMV and BPMV (PI 561353, M90-18411, PI 507353), eight were tolerant to SMV (MN 1301, M92-160047, M91-113037, PI 423826A, A99-216031, NE 3001, U96-2408, Colfax), and four were tolerant to BPMV (PI 184042, M93-326056, M95-255017, Spansoy 201). Treatment of seed with the insecticide imidacloprid (1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine) did not effect disease control. The relative level of virus antigen in seed harvested from experimental plots was shown to correlate significantly with virus incidence in plots. The data suggest that quantitative assay of virus seed antigen may provide a useful estimate of relative virus incidence in test plots and aid identification of field tolerance to seed-borne viruses.