02252nam a2200277 a 450000100080000000500110000800800410001910000180006024500900007826000160016830000110018450000620019552015410025765000140179865000140181265000100182665000160183665000130185265300140186565300140187965300240189365300100191765300140192765300150194165300180195613436812019-06-13       1982    bl uuuu  m   00u1 u    #d1 aMAGNAVACA, R.  aGenetic variability and the inheritance of aluminum tolerance in maize (Zea mays L.).  a1982.c1982  a135 f.  aDoctor Sc. Thesis. Lincoln: University of Nebraska, 1982.  aMaize genotypes were grown in nutrient solutions with different levels of Al and P to study genetic variability and the inheritance of Al tolerance. Brazilian inbred lines evaluated on acid soils of that country were substantially more tolerant than American lines when grown in nutrient solutions with added Al. responses of inbred lines to Al  levels were found to be affected by the P level in the nutrient solution. The inheritance of Al tolerance was studied in nutrient solutions with 185 uM Al and 45 uM P. Root lengths of generations (P1, P2, F1; F2, BC1 and BC2) derived from crosses between tolerant and montolerant inbred lines showed that additive gene effects explained most of the genetic variation for Al tolerance. Dominance effects accounted for abouthalf as much variation as did additive effects. Epistasis effects were small compared to the others. The frequency distributions of plants within the F2 generations were found to be continous, unimodal and typical for a quantitatively inheritance trait, with a general tendency for montolerance to be dominant over tolerance. In a diallel cross among inbred lines, the analysis of F1 crosses indicated that the variance for general combining ability explained most of the variation, but specific combining ability was always statistically significant. The original Brazilian population "Composto Amplo" and the fourth cycle of selection of grain in an acid soil that country were compared at different Al levels in nutrient solution. Root lengths of the original (...)  aAlumínio  aGenética  aMilho  aSolo Ácido  aZea Mays  aAcid soil  aAluminium  aGenetic variability  aMaize  aTolerance  aTolerancia  aVariabilidade