SUMMARY

A tissue printing hybridization (TPH) method for detecting pome fruit viroids was developed and used for a survey in Bosnia and Herzegovina. A total of 310 sam-ples, representative of 65 apple and 51 pear cultivars and of several rootstocks were tested for the presence of Apple scar skin viroid (ASSVd), Apple dimple fruit viroid (ADFVd) and Pear blister canker viroid (PBCVd). Whereas ASSVd and ADFVd were not found, 13 % of the pear samples tested by TPH gave positive signals for PBCVd that were confirmed by dot-blot and northern-blot hybridization assays. These data show for the first time that PBCVd infects pear trees (belonging to at least 10 different cultivars) in Bosnia and Herzegovina and validate the use of TPH for surveys of viroid infec-tions in pome fruit trees. Molecular characterization of the PBCVd population infecting the native pear cv Ran-cica identified five new polymorphic positions in the vi-roid genome, two of which are shared by all the se-quenced variants of this Bosnian isolate. Apple cv Spy 227 was shown to be an experimental host of PBCVd