THE RESPONSE OF SELECTED SALT‐TOLERANT AND NORMAL LINES OF FOUR GRASS SPECIES TO NaCl IN SAND CULTURE

S ummary After 7 weeks' growth in varying NaCl concentrations in sand culture, dry matter production and tiller number were compared for the progenies of NaCl–tolerant selection lines and the Progenies of unselected control lines of Holcus lanatus L., Lolium perenne L., Dactylis glomerata L. and Festuca rubra L. The tolerant lines had been produced by selection at the seedling stage. In each species, selected lines produced significantly more dry matter and had greater tiller numbers than unselected material, particularly at high levels of NaCl. Shoot/root ratios differed significantly only in L. perenne , unselected material having a higher shoot/root ratio. These data confirm that for these four species, selection based upon differences in seedling root growth is a valid means of selecting for improved NaCl tolerance in adult plants, and that this tolerance does not lead to any reduced performance in the absence of NaCl.