Abstract
Summary: Large population differentiation in salt resistance, as determined by a rooting technique, was detected among four ecologically contrasting populations at. Agrostis stolanifera L., with known genotypic compositions. It was found that an inland meadow population had a significantly lower salt resistance than the more maritime populations; and that only the inland meadow population had a significant genetical component for salt resistance.The possible adaptive value of salt resistance, as measured by the rooting technique, was evaluated in a transplant experiment in a natural salt marsh. It was found that relative root growth is a reasonable indicator of the complex of factors determining salt resistance. A detailed analysis of the relationship between salt resistance and survival within each of the four populations of A. stolonifera suggested that genotype x environment interaction and trade‐offs between characters governing salt resistance might play a significant role.