The very beginnings of plant virus nomenclature and classification were briefly mentioned and different points of view on virus names were commented on, and exemplified by 12 different proposals for the name of tobacco mosaic tobamovirus. The history and activities of the International Committee on Taxonomy of Viruses were briefly reviewed, stressing its legislation and regulation efforts. In the main part of the lecture current regulations and proposals of ICTV were presented concerning introduction of species concept and species-genus-family-order system of virus taxonomy, as well as creating a single taxonomy system for all the viruses. The main results of some research works in the field of genetics and molecular biology were reviewed forming the basis for understanding genetic diversification and speciation in plant viruses by comparing a gene structure and expression mechanisms. The proposed species names as well as those of genus, family and order are cited. Finally, current trends in virus taxonomy were presented. The implications of so-called "super-groups" and some additional proposals for new virus orders and families were discussed. The situation in the taxonomy of plant viroids was briefly commented on.
The most important data on the history, statutes and structure of ICTV are presented in connection with the earlier published data on taxonomy of plant viruses. The most important rules of virus classification are briefly commented. The content of the ICTV 7th Report is summarized: the species concept in virology, ICTV database, the classification of plant viruses within the whole virus taxonomy system and the formal status of ICTV.
Plant virus species are listed and groupped according to the content of the 7th Report of the International Committee on Taxonomy of Viruses. The proposals of Polish names are given for each virus species.