A hydroponics experiment was conducted at the Crop Science Laboratory of the University of Agriculture, Makurdi, Nigeria, in 2002 with the objective of determining the appropriate levels of aluminium for the screening of tropically adapted genotypes of soybean. Fifteen soybean genotypes constituted the main plots while ten levels of aluminium activity constituted the subplots in a split-plot design. The experiment was replicated three times. The soybean seedlings were germinated for 4 days and transferred to nutrient solutions containing the various levels of aluminium. The seedlings grew for 3 days (3D) in the hydroponics, bringing their total age to 7 days. Data were taken for primary root length, shoot length, root dry weight and shoot dry weight of plants grown at 8 levels of aluminium activity(0, 5, 50, 100, 150, 200, 250 and 300µMAl3+). No data was taken for the 350 and 400µMAl3+ levels of aluminium activity due to death of seedlings grown at these two levels. Highly significant Al, genotype, and first order interaction effects were observed. Four levels of Al activity (0, 5, 50 and 300µMAl3+) were selected and recommended as appropriate for the screening of tropically adapted genotypes of soybean.
Key words: aluminium activity, 3D, aluminium stress tolerance, hydroponics screening