Abstract
''Chinese Spring'' wheat nullisomic-tetrasomic and ditelosomic lines were used for the identification of Al-tolerance genes in wheat (T. aestivum L. em Thell.). Rye additions and substitutions in different wheat varieties were used for the identification of Al-tolerance genes in rye (S. cereale L.). The point where concentrations of Al caused irreversible damage to the root apical meristems on exposure for 24 h at 25.degree. C was the measure of Al tolerance. Genes for Al tolerance in the medium-tolerant wheat variety ''Chinese Spring'' were localized in chromosome arms 6AL, 7AS, 2DL, 3DL, 4DL and 4BL and on chromosome 7D. Major genes for tolerance in rye seem to be located on 3R and 6RS, with other genes on 4R. The expression of Al-tolerance genes located on rye chromosomes incorporated into sensitive wheat was often suppressed by the action of unknown genes in the wheat background.