Induction of mild strains of pepper mottle virus by chemical mutagenesis and their efficacy in cross protection

Crude sap of pepper Capsicum frutescens L. 'NM 6-4' infected with pepper mottle virus (PeMV) was treated with nitrous acid to induce mutants. Twelve isolates were selected from two distinct types of local lesions on Capsicum frutescens L. 'tabasco'. Of the twelve isolates, four produced mild symptoms on both pepper foliage and fruit. When these mild isolates were inoculated to pepper plants and subsequently challenged with wild type PeMV, they protected the plants from the severe effect of the wild type isolate. Marketable pepper fruit from these protected plants was not significantly different from fruit from uninfected pepper plants.