Differential response and genetic analysis of acidic stress tolerance, with particular reference to aluminium stress tolerance in triticale

Abstract

Differential aluminium (Al) resistance responses can be established through measurement of root re-growth characters in hydroponics with a modified Al pulse method. A screening concentration of 10 mg·L⁻¹ Al (pH 4.5) imposed for 24 hr duration provides efficient discrimination between resistant and sensitive cultivars. The extent of root re-growth provides useful indices of Al resistance.

A dialler analysis indicated that parental performance is a useful indicator of Al stress response in their progenies, and a breeding program may initially rate potential parents on this basis for their Al stress response. Three Al-tolerant genotypes, Tahara, Abacus and 19th ITSN 70-4, were found to be good general combiners for large root re-growth, they could be used in hybridisation programs to improve Al resistance. The information generated will assist decisions on parental selection for a more extensive study of inheritance of Al resistance response in hydroponics.

Comparisons between Al pulse method-assessed seedling Al resistance and adult plant performance under acid soil conditions indicated a reasonable agreement between these two different cultures of genotypic Al response. Genotypes having superior performance in acid soils were assessed as either Al-resistant or moderately Al-resistant by the hydroponic system technique. These data suggest that the Al pulse method can provide a useful guide to field performance where Al toxicity is a component of the acid soil stress.