Factors Affecting the Incidence of Systemic Necrosis in F₁ Hybrid Tomato Plants Resistant to Tobacco Mosaic Virus. M. Pilowsky, Division of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel 50-250. Plant Dis. 65:684-686. Accepted for publication 3 December 1980. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-684.

In tomato plants heterozygous for the Tm-2^a gene for tobacco mosaic virus localization, the incidence of systemic necrosis at high temperature (30–31 C) decreased with increase in plant age at the time of inoculation with an isolate of TMV strain 0. Similarly, fewer plants were necrotic when the length of exposure to high temperature was reduced and the time interval from inoculation to the heat treatment was extended. The presence of a certain amount of virus at the primary site of infection may be necessary for systemic necrosis to develop at high temperature.

Keyword(s): Lycopersicon esculentum, tobacco mosaic virus infectivity.