TOLERANCE OF AUSTRALIAN WHEAT-VARIETIES TO ALUMINUM TOXICITY

This paper reports the reaction of 24 Australian wheats and 16 overseas cultivars to high aluminium (A1) in solution culture. These results are compared with those from a rapid haematoxylin stain test. The relationship between the haematoxylin stain test results and performance in the field was also determined. The dry matter yields in solution culture confirmed tolerances previously reported for the non-Australian cultivars, with only two exceptions. The Australian varieties vary in tolerance but none were as tolerant as those from Brazil. The tolerances of the Australian varieties were not related to the breeding origins of the varieties. Exposure to Al in solution differentially reduced the concentration of calcium (Ca), magnesium (Mg), and phosphorus (P) in both shoots and roots. The more Al-tolerant varieties were less affected. The results obtained in solution culture and in the haematoxylin stain test generally agreed, but more differences between varieties were noted in solution culture results. The haematoxylin stain test was then used to classify cultivars and advanced lines in the breeding programme, and the results were compared with yield performance on acid (8 sites) and non-acid soils (20 sites). The lines in haematoxylin class 4 had a 20% yield advantage over the acid sites. We concluded that tolerance was useful in the field, that the haematoxylin stain test is useful as a rapid preliminary assessment of Al tolerance, and that the prospect of breeding cultivars with improved tolerance was rewarding.