Evaluation of aluminum tolerance of three barley cultivars by two short-term screening methods and field experiments

Productivity of cereal crops growing in acid soils of Southern Chile have a dversely being affected by acidification and aluminum phytotoxicity, For ov ercoming such constraints, farmers need to apply heavy amounts of lime and/ or use Al-tolerant plants especially with Al-sensitive crops, as barley is, The objectives of this study mere to determine the degree of Al tolerance of three barley cultivars commonly grown in volcanic soils by using two sho rtterm screening methods and to relate their rankings with field experiment s, Additionally, the amounts of citric and malic acids exuded from roots we re determined for studying the mechanism involved in Al tolerance, Relative root length (RRL) was the criterion used to evaluate Al tolerance both in nutrient solution and in soil-based culture and yield for field experiments . Results showed a close relationship between the RRL values obtained with the three barley cultivars by applying the two short-term screening methods , Barley yields obtained in field experiments carried out in two soils diff ering in Al contents agreed well with the ranking observed in the laborator y suggesting that the short-term screening methods could be a useful tool f or knowing Al tolerance of cereals habitually cropped in our acidic volcani c soils, Citric and malic acids were detected mainly in the exudates from t he most Al-tolerant barley which could indicate a chelation mechanism impli ed in such a tolerance.