Evaluation of aluminium tolerance in a spring rye collection by hydroponic screening.

Aluminium (Al) tolerance of 63 rye accessions from a world spring rye collection was evaluated using the haematoxylin method and the root growth method. The haematoxylin method is based on the ability of Al-tolerant seedlings to continue root growth following a short pulse treatment with a high Al concentration, while the root growth method uses the root growth and root tolerance index to judge Al tolerance. Significantly higher levels of Al tolerance were found in rye than in the Al-tolerant bread wheat cultivar `Maringa'. Under the assumption that the ability of roots to grow under Al stress is a combination of root vigour (long roots) and Al tolerance, a hypothesis allowing for the differentiation of five genotype classes was suggested. This study demonstrated that the haematoxylin method and the root growth parameter identify genotypes with long root growth under Al stress, but failed to detect Al tolerance in genotypes with poor root vigour. These genotypes can only be identified using the root tolerance index parameter. However, the haematoxylin method is highly suitable for screening large segregating populations derived from improved germplasm that has been preselected for agronomically preferable traits, including plant vigour. [ABSTRACT FROM AUTHOR]