Sequences from the coat protein cistron of five ryegrass mosaic virus (RgMV
) isolates indicated the presence of two distinct strains in New Zealand. T
he nucleotide differences between the strains, and their distribution, sugg
ested that both strains were introduced recently, either as a mixed infecti
on or as two independent introductions, The relationship between these New
Zealand strains and other strains and isolates of RgMV, and their potential
severity is discussed.