Thermal inactivation of cherry leaf roll virus in tissue cultures of Nicotiana rustica raised from seeds and meristem‐tips

SUMMARY Nicotiana rustica tissue cultures derived from seeds or embryos infected with cherry leaf roll virus (CLRV), remained infected after culture at 22 o C. No infectivity was found in cultures held at 32 o C for 5 days but it was readily detected after such cultures were transferred to 25 o C for 8 days. Virus was permanently eradicated from most plants after 20 days incubation at 32 o C and from all plants after 7 days incubation at 40 o C. Partially purified preparations of CLRV lost infectivity after 9–12 days at 22 o C, 5 days at 32 o C and 3 days at 40 o C.