Detection of Potato Leafroll Virus in Primarily Infected Tubers by Enzyme‐Linked Immunosorbent Assay

Abstract

The effects of artificially breaking dormancy on the detection of potato leafroll virus (PLRV) in tubers of four field‐grown potato cultivars with primary infection were studied by ELISA. Treatment with Rindite increased the concentration of PLRV at the rose end of tubers to a level which exceeded in the susceptible cv. Sieglinde that of the heel end and was in cultivars Sirco and Dirus almost as high as that of the heel end. PLRV concentration was highest at four weeks after Rindite treatment and remained on a much higher level in treated tubers from August till November than in untreated ones. At 14 weeks after breaking dormancy, PLRV dropped in treated tubers to a very low level which was similar to that of untreated ones. With sprouting tubers of cv. Jetta, PLRV occurred at significantly higher concentrations in samples from rose‐end eye tissue than in those from heel‐end tissue next to an eye. The reliability of detecting PLRV was higher in treated tubers than in untreated ones and did not depend upon the tuber end tested. With the exception of cv. Sieglinde, all infected tubers which could not be detected by ELISA in the tuber test originated from late‐inoculated plants. PLRV was reliably detected in sprouts. ELISA on leaves of field‐grown plants with primary infection gave very unsatisfactory results, irrespective of the time of inoculation.