Growth and Dry Matter Partitioning of Common Bean (Phaseolus vulgaris L.) Genotypes as Influenced by Aluminum Toxicity

Aims: This study was conducted to assess effects of different exchangeable aluminium concentrations on growth and dry matter partitioning of two common bean genotypes (new BILFA 58 and Roba 1) grown on lime-treated and lime-untreated acid soils.

Study Design: Factorial combinations of five rates of aluminium (0.0, 12.5, 25.0, 50.0, and 100.0 mg Al kg-1 soil) and two genotypes were laid out in a completely randomized design of three replications.

Place and Duration of Study: The experiment was conducted in the vegetation hall of Nekemte Soil Laboratory, western Ethiopia from July to October, 2011.

Methodology: For each treatment, four plants were raised per pot, data related to growth and dry matter partitioning of the crop were collected at 25 and 35 days after seedling emergence (DAE).

Results: Aluminium rate and genotype interaction had significantly (P=0.01) affected all parameters considered except relative growth rate and shoot to root weight ratio for lime-untreated soil, and specific leaf area, leaf fraction and leaf area for lime-treated soil. A significant growth reduction was found on lime-untreated soil than treated soil, particularly as aluminium applied increased. On average, application of aluminium led to 37.5, 32.9, and 35.7% reduction in absolute and relative growths, and net assimilation rates. The differences due to aluminium rate and genotype were also significant for dry matter partitioning and root to shoot ratio. On both lime-treated and untreated soils, dry matter partitioning to root was higher for new BILFA 58 than for Roba 1 at 25 and 35 DAE.

Conclusions: Application of aluminium had a significant adverse effect and decreased the growth of two genotypes under both lime-treated and untreated soils. However, growth reductions were lower on lime-treated soil than untreated soil and genotype new BILFA 58 had performed better than Roba 1 under increased soil acidity and aluminium concentration.