Diallel analysis and mapping of aluminum tolerance in corn inbred lines.

Toxicity by aluminum is one of the main limitations for production in cropping areas, including corn (Zea mays L.) cultivation. There is genetic variability for the aluminum tolerance traits in corn but selection is troublesome because field assessment is difficult. The ob- jective of the present study was to characterize aluminum tolerance in five corn inbred lines and to identify chromo- somal regions associated to this resistance. A diallel ex- periment was conducted between three aluminum sensi- tive and two aluminum tolerant lines using the root re- growth method. The hybrid populations were superior compared with the parents and, from the partitioning of the heterosis effects; there were significant variety hetero- sis and specific heterosis effects. Lines L06 and L09 showed greater general combining ability and the L10 x L08 cross presented the best specific combination. Molec- ular mapping was performed with SSR in an F3 genera- tion from the cross L10 x L08. Data analysis showed five QTL, which explained 41% and 37% for root re-growth and hematoxylin staining. The results suggested that alu- minum resistance in corn have complex inheritance deter- mined by additive and non additive genetic effects.