RESISTANCE TO TOMATO YELLOW MOSAIC-VIRUS IN SPECIES OF LYCOPERSICON

Diseases caused by geminiviruses are widespread in the tropical-subtro pical tomato production areas. Tomato yellow mosaic geminivirus (ToYMV ) is a member of the whitefly-transmitted subgroup (III), which is vec tored by the whitefly Bemisia tabaci. Several accessions of Lycopersic on con chilense, L. hirsutum, and L. peruvianum var. glandulosum were identified that exhibit tolerance or a high degree of resistance to a Venezuelan isolate of ToYMV in field and greenhouse studies using mech anical inoculation and viruliferous vectors. Polymerase chain reaction analysis showed that viral DNA is present in infected plants and abse nt in resistant ones. Mechanical and insect transmission gave differen t results in some species or cultivars, suggesting a distinct mechanis m for resistance.