Resistances in Rice to Tungro-Associated Viruses

Tungro is a composite disease associated with rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV). Over a period of 23 yr, 40,000 rice germ plasm accessions were evaluated for resistance to tungro by greenhouse mass inoculation using the vector green leafhopper (GLH), Nephotettix virescens. From those, 119 cultivars that showed low levels of infection were selected. Each seedling of the selected cultivars was exposed in a test tube to five GLH that had fed on plants infected with either both RTBV or RTSV alone. Inoculated seedlings were indexed by enzyme-linked immunosorbent assay (ELISA)