Potato Virus M and Paracrinkle

Abstract

THE discovery by Dr. B. Kassanis that 90 per cent of plants in two stocks of King Edward contained only paracrinkle virus and were free from virus S suggests that virus S entered King Edward stocks later than did paracrinkle virus (virus M). The King Edward used by us¹ was possibly derived from Salaman's original material, as the plants investigated were the descendants of occasional Red King mutants found in a stock being propagated by the National Institute of Agricultural Botany and which had originally been supplied by Salaman². Similarly, the King Edward stock investigated by Bagnall, Larson and Walker³ in the United States, and which also contained both viruses S and M, was obtained indirectly from Salaman. This suggests that the stock of King Edward used by Salaman and Le Pelley⁴ may have contained both viruses S and M, although, of course, stocks at the National Institute of Agricultural Botany and those in the United States could have picked up virus S at a later date.