Abstract
Two near-isogenic sorghum (S. bicolor) inbreds, Combine Kafir 60 (CK60) and Kansas line 56 (KS56), were inoculated with maize dwarf mosaic virus strain A at 3 plant-growth stages. These inbreds differed in their responses to viral infections; under cool temperatures, CK60 developed tissue necrosis (red leaf disease) and KS56 a mosaic symptom. Results showed statistically significant yield losses with all virus treatments compared with their respective controls. At the earliest growth stage, yields of inoculated CK60 and KS56 were reduced 61 and 26%, respectively.