Use of Microwave Energy for the Eradication of SeedborneMaporthe Phaseolorumin Soybean and Its Effect on Seed Quality

The effects of various levels of absorbed microwave power (AMP) and duty cycle (DUC) on the germination, seedling vigor and infection levels of soybean seeds starting at different initial moisture contents (IMC) were studied. The test pathogen was Diaporthe phaseolorum. Unlike most microwave experiments on seed, the inlet airflow was nil. The treatment time was 30 mm in all cases. Germination and seedling vigor were both reduced at high levels of energy input (high AMP or DUC, or both). Of course, the opposite effect, level infection by the pathogen, was also reduced under such conditions. All reductions were less drastic at the higher initial moisture contents. Statistical models explained 91, 89 and 81% of variations in germination, vigor index and percentage seed infection, respectively. The models indicated that irregardless of the other conditions, a DUC 30 reduced all quality parameters to below acceptable levels, but also significantly reduced infection levels. According to the model, the minimum level of infection that can be obtained while maintaining germination and vigor at acceptable levels is in the vicinity of 12%.