BARLEY YELLOW DWARF VIRUS ISOLATE-SPECIFIC RESISTANCE IN SPRING OATS REDUCED VIRUS ACCUMULATION AND APHID TRANSMISSION

Resistance to barley yellow dwarf virus in a spring oat genotype was manifested as a reduction in accumulation of viral antigen in whole plants. The resistance was quantified for five isolates of BYDV from New York (MAV, PAV, SGV, RPV, and RMV) and found to be BYDV isolate specific. Similar levels of resistance were quantified for MAV, PAV, and SGV in which the reduction in viral antigen ranged from 58-63 percent, relative to levels in a susceptible genotype. RMV antigen was reduced up to 82 percent, but no resistance was expressed against the RPV isolate. Reduced viral antigen was correlated with reduced levels of transmission of MAV, PAV, SGV, and RMV, but not RPV. Further reductions in transmission efficiency were possible by limiting the acquisition access period. Resistance to circulative, nonpropagative, aphid-borne viruses manifested as a reduction in virus antigen may reduce the spread of disease among plants, especially if coupled with aphid resistance manifested as a feeding deterrent.