Abstract
Five strains of cucumber mosaic virus (CMV) were distinguished in the isolates of viruses which attack cucumber in Czechoslovakia (Havránek 1970). The strains A, B, C, D, and E of CMV were defined according to different syndromes onNicotiana tabacum L.,N. glutinosa L.,Phaseolus vulgaris L. andChenopodium polyspermum L. The Czechoslovak strains, in comparison with American ones, did not cause systemic disease inCucumis anguria L. orCucurbita moschata Duch., but strains D and E of CMV suppressed the tolerance of American cucumber cultivar Wisconsin SMR 18. The propertiesin vitro of isolated CMV strains correspond to the description of CMV, but we did not succeed in establishing their antigenic behaviour. The relation of the Czechoslovak CMV strains to those described in publications is discussed.