This research aimed to investigate reaction of sweet pepper (Capsicum annuum L.) progenies to an isolate of Potato virus Y (PVY) from cv. Magda, from Paulínia, State of São Paulo, Brazil, and to identify this isolate. The identification was made by biological tests, using host plants, and by serological tests (TAS-ELISA) employing monoclonal antibodies against the PVY0, PVY N and PVY C strains. Thirty five progenies, from the IAC improvement program, were inoculated with this isolate, named PVY-Pa, and five commercial cultivars whose reaction to PVY was known were used as positive control. In these experiments a completely randomized design was used. Biological tests and electron microscopy showed a mixed infection by potyvirus and tobamovirus in the original samples of sweet pepper. The PVY was isolated from Nicotiana glutinosa leaves with systemic symptoms and in ultra-thin sections, cylindrical cytoplasmic inclusions like pinwheels, were recognized. Such cytopathic effect is unique for the family Potyviridae. In TAS-ELISA infected samples of N. glutinosa reacted negatively against the monoclonal antibodies employed. However, the absence of symptoms on 'Myr 10' and 'Myr 29'Capsicum cultivars was associated with PVYm strain. Resistance of the sweet pepper progenies was assessed through the ratio between the absence and presence of symptoms. From such progenies, seven F3 three-way hybrid progenies showed assymptomatic plants from which the virus could not be recovered by inoculation on N. glutinosa, thus confirming that the virus does not multiply in those progenies.
Capsicum annuum L.; vegetable breeding; Potato virus Y; genetic resistance
