Aluminium tolerance in soybean seedlings and its utilization

Abstract

Seedlings of 23 soybean genotypes were evaluated for aluminium tolerance in hydroponics from seeds previously germinated and transferred to solution containing 100 mg/kg Ca, combined to the levels of 1.5 and 3.0 mg/kg aluminium, defined in a previous experiment, with the pH adjusted to 4.0. The time interval required for conducting the experiment was of four days. Al-reaction was evaluated by direct measurement and hematoxylin staining. In staining with hematoxylin the cultivars showed inconsistent results and differed from those obtained in the root measurements. The root elongation is highly influenced by seed vigour and handling techniques. These limiting factors were overcome by standardizing radicle length before the tests and by increasing the number of individuals per replicate. The genotypes were classified between highly tolerant and susceptible. Among commercial cultivars, 'Doko', 'Cristalina', 'Tropical' and 'BR-9 (Savana)' were superior to 'IAC-9' standard for aluminium tolerance.