Three test series were planted on sites selected for their contrasting properties to study the genotype × site interaction. Various clones ofSalix alba(8 clones in the 1980 series),S. dasyclados(8 clones in 1982 series) andS. viminalis(6, 9, 13 clones in the various series) were included. Growth capacity, survival and infection by rust fungi were analysed. Interspecific variation was seen at some of the sites in the 1982 series but it was pronounced in the 1980 series where 5.viminalisoutgrew 5.albaat all sites. Intraspecific variation could be seen for growth capacity, survival and rust resistance. A genotype × site interaction was detected for all variables studied. Some of the interaction, especially at the species level, can be explained by the variation in susceptibility to rust fungi and preference for soil types. In the breeding work withSalixthe genotype × site interaction must be considered.