| Abstract: | In greenhouse experiments with small pots, seeds of cowpea (Vigna unguiculata) were planted into an acid soil (Oxic Paleudult from Onne, South-East Nigeria) which had been treated with Al2(SO4)3-Cowpea genotypes showed varying seedling growth inhibition within 7 days when grown in soil containing 2.2 meq Al/100 g soil. Soil and plant analysis confirmed, that Al toxicity, and consequently differences in Al tolerance, were responsible for the genotypically different seedling growth responses. 783 genotypes showed a wide range of Al tolerance when screened using this technique. In a long-term pot experiment the effect of Al application to the soil on seed yields of 9 genotypes was studied. Although no significant correlation could be found between depression by Al of seedling growth and grain yield of the genotypes, the same genotypes were classified as most tolerant and most sensitive in both cases. The results show that the simple and quick screening method using Al-treated soil allows the identification of genotypes adapted to soils with high Al supply. |
