Potato Virus M and Paracrinkle

Abstract

Salaman and Le Pelley¹ found that scions of apparently healthy plants of the potato variety King Edward VII grafted on to supposedly virus-free Arran Victory resulted in the latter variety reacting with paracrinkle symptoms, that is, a pronounced deformity and rugosity of the leaves. Although both Kassanis² and Macarthur³ suggest that King Edward contains only a single virus, Bagnall, Larson and Walker⁴ found that a stock of King Edward, which they obtained from Canada and which had been supplied originally by Salaman, contained two viruses. One was a strain of virus S and the other resembled virus M which they had found in Irish Cobbler and several other American varieties. All normal stocks of Arran Victory were found by Macarthur³ to contain virus S. Therefore, even if there are stocks of King Edward with only a single virus, the paracrinkle symptoms observed in Arran Victory after grafting with King Edward may be due either to the King Edward virus (presumably virus M) alone or to the combined action of viruses S and M, as is suggested by Bagnall, Wetter and Larson⁵.