02100naa a2200397 a 450000100080000000500110000800800410001910000180006024500940007826000090017252010530018165000150123465000160124965000140126565000190127965000130129865000140131165000140132565000120133965000260135165000250137765000160140265000200141865000350143865000140147365000090148765000160149665300140151265300130152665300210153965300240156065300140158465300150159870000180161377300710163115517021996-05-24       1996    bl ---       0--  u    #d1 aSPEHAR, C. R.  aDiallel analysis for aluminium tolerance in tropical soybeans [Glycine max (L.) Merrill].  c1996  aThe soybean is a major crop in the agricultural systems of the Brazilian Cerrados (Savannahs), whose soils are acidic, devoid of nutrients and need to be amended before they are cultivated. However, below the ploughed layer there is a scarcity of nutrients and toxic aluminium (Al). These limit root growth, subsequently causing nutritional imbalance and drought stress. Our aim in the investigation described here was to identify genetic differences in the aluminium tolerance of soybeans by a 9 x 9 diallel cross among contrasting varieties grown in high-Al areas and in hydroponics. Combining ability analysis indicated predominantly additive gene effects, and the additive-dominance model explained most of the genetic differences in this germplasm for mineral element absorption and root growth under aluminium stress. The relationship between the two factors suggest that conjugation hydroponies and field evaluations in breeding programmes would further improve soybeans with respect to yield stability under tropical cultivation conditions.  aacid soils  ahydroponics  anutrients  aplant breeding  asoybeans  avarieties  aAlumínio  aCerrado  aCruzamento Dialélico  aCultivo Hidropônico  aGlycine Max  aHereditariedade  aMelhoramento Genético Vegetal  aNutriente  aSoja  aSolo Ácido  aAluminium  aCultivar  aDiallel crossing  aGenetic inheritance  aTolerance  aTolerancia1 aGALWEY, N. W.  tTheoretical and Applied Genetics, New Yorkgv.92, p.267-272, 1996.