Fourteen wheat genotypes (mutant lines and cultivars) were evaluated in relation to the primary root growth, during 7 and 15 days of development, in aerated nutrient solutions, under laboratory conditions, in two experiments, carried out in randomized block design with two replications. In the first experiment, pH (4.0) and temperature (24 ± 1ºC) were kept constant. Four different salt concentrations (1/1, 1/2, 1/5 and 1/10 of regular nutrient solution) were utilized. In the second experiment complete solutions with three different pHs (4.0, 5.0 and 6.0) were used, keeping the temperature constant (24 ± 1ºC). The analysis of variance of the root growth means after 7 and 15 days of experiments 1 and 2, showed significant effects for genotypes, salt concentrations and pHs of the solutions and non significant effects for genotypes x salt concentrations or genotypes x pHs interactions. High genetic variability was observed among the genotypes in relation to root growth, regardless the pH, salt concentration or period of growth. The genotypes 6 (BH-1146) and 23 (KAUZ"S"/IAC-24 M2) presented intense root growth in the first stages of development (7 and 15 days). The Al3+ tolerant genotypes 25 (KAUZ"S"/IAC-24 M4), 27 (KAUZ"S"/IAC-24 M6), 37 (TUI"S"/IAC-24 M2), 40 (IAC-287/IAC-24 M1), 41 (IAC-287/IAC-24 M2), 42 (IAC-287/IAC-24 M3), 44 (IAC-287/IAC-24 M4) and the Al3+ sensisitive genotype 32 (KAUZ"S") showed reduced root growth in the same conditions.
primary roots; breeding; aluminum; tolerance
