The Selective Inactivation of Seed-Borne Soybean Mosaic Virus by Exposure to Microwaves

Abstract

Soybean (Amsoy 71) seeds infected with soybean mosaic virus (SMV) were treated by exposure to 675 W of microwave power at 2450 MHz for varying times and at two different levels of moisture content. A selective inactivation of the seed-borne SMV was achieved with little or no reduction in the germination rate. The seed-transmitted virus was reduced from 45% to 7% in the low moisture (8.5%) soybeans after a 160 s exposure to microwaves. At this exposure time the temperature of the soybeans was raised from 22° to 42°C and the germination rate remained at about 100%. The soybeans with a high moisture content (16%) absorbed microwave power more readily than the soybeans of 8% moisture owing to the difference in water content. They heated more rapidly and it was found that both the SMV and the germination were considerably reduced. It is suggested that the high moisture soybeans be first dried to less than 10% moisture before the seed-borne virus can be successfully inactivated by exposure to predetermined doses of microwave energy with negligible effect on the germination.