Occurrence of the Andean strain of potato virus S in imported potato material and its effects on potato cultivars

Abstract

Infection with potato virus S Andean (PVS A ) and ordinary (PVS o ) strains was found in potato breeder's selection No. 8163‐511 imported from West Germany; the two PVS strains were differentiated by their reactions on Chenopodium quinoa Tests on potato leaf samples using enzyme‐linked immunosorbent assay followed by inoculation to C quinoa were subsequently used to detect PVS A and PVS o in a large‐scale survey of imported and domestic potato material. PVS A was detected in breeders' selections and cultivars imported from the Netherlands and West Germany, but not in domestic certified seed potato stocks or farmers' once‐grown stocks. PVS o was found in both imported and domestic certified stocks, but infection was commoner in the imported ones. When plants of C. quinoa, C. amaranticolor, C. murale and Nicotiana debneyi were inoculated with four isolates of PVS A , one induced mild symptoms while the reactions of the others ranged from moderate to severe. When plants of different potato cultivars were inoculated with three isolates, the plants were mostly infected without symptoms. However, when tubers from some were grown on, the progeny plants of most of the different combinations of cultivar and isolate of PVS A developed one or more of the following symptoms: vein deepening, rugosity, interveinal chlorosis, premature senescence and early loss of lower leaves.