Genetic control of aluminum tolerance in mutant lines of the wheat cultivar Anahuac

The behavior of 17 gamma irradiation mutant lines derived from the aluminum sensitive wheat cultivar 'Anahuac' was compared with two sensitive and thr ee tolerant cultivars in nutritent solutions containing seven Al3+ concentr ations (0; 0.5; 1; 2; 4; 6 and 10 mg/liter), at a temperature of 25 degrees C and 4.0 pH. Tolerance was measured by the continued growth of the primar y roots in a solution without aluminum after 48 hours in a solution contain ing a known concentration of aluminum. 14 mutant lines were as tolerant to the presence of 10 mg/liter of Al3+ in the treatment solutions as were the tolerant 'BH-1146', 'IAC-60' and 'IAC-24' cultivars. Two mutant lines were tolerant and one was sensitive to the presence of 1 mg/liter of Al3+, while the cultivars 'Siete Cerros' and 'Anahuac' were sensitive to 1 and 0.5 mg/ liter Al3+ in the solutions, respectively. F-2 seedlings, obtained from cro ss among one sensitive and twelve tolerant mutant lines to the sensitive cu ltivars ('Siete Cerros' or 'Anahuac') and the tolerant cultivars ('BH-1146' or 'IAC-24') were assessed for tolerance to 2 mg/liter Al3+ in nutritient solutions. The twelve tolerant mutant lines and the tolerant 'IAC-60' and ' IAC-24' cultivars differed from the sensitive 'Siete Cerros' or 'Anahuac' c ultivars by one pair of dominant alleles. The results indicated that tolera nce in the induced mutants was due to a single pair of dominant alleles and that these alleles expressed the same tolerance as 'BH-1146' and 'IAC-24' cultivars.