RESISTANCE OF POTATO TO CUCUMBER MOSAIC-VIRUS APPEARS RELATED TO LOCALIZATION IN INOCULATED LEAVES

Although CMV can cause extensive damage to solanaceous crops like toma to, tobacco and pepper, it has little if any impact on the related cro p, potato. To better understand this phenomenon, we have tested 32 pot ato genotypes for susceptibility or resistance to local and systemic F ny-CMV infection. Using ELISA, all genotypes appeared to show virus re plication in leaves that were mechanically inoculated. In contrast, on ly ten genotypes exhibited systemic spread as expressed by significant CMV titers in new growth. These data suggest that, although CMV can r eplicate in potato cells and appears to spread short distances cell-to -cell, long distance movement appears to be blocked in most potato gen otypes. Therefore, the general resistance of potato crops to CMV infec tion may be related to virus localization at points of entry.