The cultivar Siete Cerros (P1) with tolerance to manganese toxicity and the cultivar BH-1146 (P2) showing sensitivity to manganese, were crossed. It was obtained the F1 and F2 generations of this cross. P1, P2, F1 and F2, where cultivated in nutrient solutions containing 0.11, 300, 600 and 1,200mg/l of manganese and they also were tested in other nutrient solution with 3mg/l of aluminum. The length of the central primary root of plants of each genotype under study after fifteen days being cultivated in nutrient solutions containing different manganese concentrations was used to evaluate the levels of tolerance to this element. The length of the central primary root of plants of each genotype measured 72 hours in a normal nutrient solution after a previous test in a treatment solution containing 3mg/l of aluminum was considered to evaluate the degree of tolerance to aluminum toxicity. The broad sense heritabilities values of root length considering increasing levels of manganese in the solution and 3mg/l of aluminum were high which indicated that the present variability found in the populations were in great part due to genetic origin. These results suggested that selections for tolerance to aluminum and manganese toxicities would be effective in early generations of a cross. The data showed that it would be possible to transfer by crossing BH-1146 and Siete Cerros the genetic tolerance to manganese from Siete Cerros into the BH-1146 germplasm or to obtain a Siete Cerros germplasm with aluminum tolerance from BH-1146 source.