INVESTIGATIONS ON THE SEROLOGICAL DETECTI ON OF TOMATO SPOTTED WILT VIRUS (TSWV) IN TOMATO AND BASIL IN CONNECTION WITH RESISTANCE TESTS

Using a modified procedure of partial purification according to TAS et al. (1977), antisera of tomato spotted wilt virus (TSWV) were prepare d which could be applied successfully in the serological retesting of breeding material obtained from resistance tests. In view of the relia ble serological diagnosis of TSWV, the sporadic distribution of this v irus in plants of tomato and basil has to be considered by taking appr opriate mixed samples. In comparative investigations with four isolate s of TSWV isolated from Lycopersicon esculentum Mill., Ocimum basilicu m L. and Impntiens wallerana Hook., respectively, we found significant differences as to their virulence in spire of uniform regional origin . Compared to the other three isolates, the isolate derived from I. wa llerana was characterized by a delayed development of very mild sympto ms as well as by a lower percentage of infected plants, e.g., at L. es culentum or Nicotiana glutinosa L. However, the rested isolates coinci ded in their serological properties. In order to assess an unknown iso late, we regard it as sufficient to use its reaction on N. glutinosa, but always in comparison with an isolate of known virulence.