Evaluation location: Arkansas, United States
G. max accessions were planted in 15-cm diameter plastic pots filled with a commercial soil mix in the greenhouse. The temperature was maintained at 25 C with a 12-h photoperiod. Twelve seeds were planted in each pot, and plants were thinned to eight per pot for inoculation. Plants were inoculated with the K-Ho1 isolate of BPMV at the unifoliolate stage. For each entry, three pots of plants were inoculated with leaf sap from healthy plants as a control and three pots of plants were inoculated with each virus isolate. Plants were monitored for symptom expression for 3 weeks, and presence of virus was determined by enzyme-linked immunosorbent assay (ELISA) 3 weeks after inoculation. The middle leaflet from young, fully expanded, uppermost trifoliolate leaves above the inoculated leaves was collected from each plant in each pot and mixed as one sample for the ELISA assay. Reactions to BPMV were classified as mild, moderate, or severe based on symptom expression.