Abstract
Rice is a highly Al-resistant species among small grain crops, but the mechanism responsible for the high Al resistance has not been understood. Rice mutants which are sensitive to Al were isolated from M3 lines derived from a cultivar of Koshihikari radiated with γ-ray. Relative root elongation (RRE) was used as a parameter for evaluating Al resistance. After 3 rounds screening, two mutants (Alsr17, Alsr22) were isolated from F3 560 lines. These mutants showed highly Al sensitive compared with the wild type (WT, Koshihikari). Root elongation was hardly inhibited by 30*M Al in the WT, but was inhibited by 80% and 90%, respectively, in the mutant Alsr17and Alsr22. The Al content of root apices (0-1 cm) was much lower in the WT than in the two mutants. Further characterization of these mutants and mapping of responsible genes are currently being undertaken.
