A Genetic Analysis of Aluminium Tolerance in Cereals

Aluminium (Al) toxicity is a major threat to agricultural production world wide wherever acid soil exists. Wheat and barley, the major food and feed crops, are severely aff ected and this necessitates investigations that could help to improve the yield by utilising the available genetic diversity for Al tolerance with the aid of several molecular platforms. We investigated the quantitative trait loci (QTL) conferring tolerance to Al toxicity in three diff erent mapping populations of wheat and barley. Using a set of D genome (Ae. tauschii) introgression lines, a major Al tolerance locus was assigned to chromosome arm 4DL, explaining 31% of the phenotypic variation displayed by the population. A second major QTL was mapped to chromosome arm 3BL using a set of doubled haploid progeny lines. Th is major QTL, QaltCS.ipk-3B, originated from ‘Chinese Spring’ accounted for 49% of the variation in the population. Th e inheritance for Al tolerance in barley was dissected based on a genetic map constructed with genic markers. QTLs were identifi ed on chromosomes 2H, 3H and 4H. A sequence homology search was used to derive the putative function of the genes linked to the QTL, in order to identify potential candidate genes for Al tolerance. Some of these candidates are implicated in stress/defence responses, in particular, stress signal transduction, transcription regulation factors and cell metabolism.