8th INTERNATIONAL WHEAT CONFERENCE

ToLeRANCe To IoN ToxICITIeS (AL, mN ANd fe):
AN oPPoRTuNITy To ImPRoVe WheAT PeRfoRmANCe
IN WATeRLoggINg-PRoNe ACId SoILS
Hossein Khabaz-Saberi 1 , Robin Wilson 2 & Zed Rengel 1
1 Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling
Highway, Crawley, WA 6009, Australia.
2 Department of Agriculture and Food Western Australia (DAFWA), 3 Baron-Hay Court,
South Perth 6151. Australia
E-mail Address of presenting author: hsaberi@cyllene.uwa.edu.au
High concentrations of manganese (Mn) and ferrous iron (Fe 2+ ) induced in water-saturated
acid soils are a potential constraint for growing sensitive wheat cultivars in high
rainfall areas of Western Australian wheat-belt. The tolerance to ion toxicities within current
hexaploid Australian wheat germplasm was investigated to find out the extent of
variation.
Significant variation in Mn and Fe tolerance in terms of relative root dry weight and
toxicity symptoms was observed. The evidence suggested that Mn tolerance has been
introduced into Australian wheat through CIMMYT germplasm having “LERMA-ROJO”
within their parentage, preserved through either co-tolerance to Mn deficiency or passive
selection for Mn tolerance. Cultivars Westonia and Krichauff expressed a high level of
tolerance to both Mn toxicity and deficiency, whereas Trident and Janz (reputed to be
tolerant to Mn deficiency) were intolerant to Mn toxicity, suggesting that tolerances to
Mn excess and Mn deficiency are different, but not mutually exclusive traits.
Genotypes Amery, WAWHT2856, EGA2248, Bowie, Sunco and QAL2000 were as Fe-tolerant
as Siete Cerros (Fe-tolerant control), whereas Annuello, WAWHT2036, GBA-Ruby
and Kalannie expressed a level of intolerance similar to BH1146 (Fe-sensitive control).
Siete Cerros has been traditionally used for improvement of agronomic traits in breeding
programs around the world; hence, it as a progenitor of many Australian varieties.
However, we suggest that the observed variation among Australian wheat genotypes for
Fe tolerance might be due to indirect selection rather than selection pressure for either
quality parameters or agronomic traits.
The existing variation for tolerance to ion toxicities provided a required tool to investigate a
link between tolerances to ion toxicities and improved waterlogging tolerance in wheat. In
terms of relative shoot dry weight, Al-, Mn- and Fe-tolerant genotypes were more tolerant
to waterlogging, outperforming intolerant genotypes by 35, 53 and 32 %, respectively,
across the three acidic soils. Al-tolerant genotype had up to 1.8-fold better root growth
than intolerant genotype under waterlogging. Waterlogging increased DTPA-extractable
soil Mn (71%) and Fe (89%) concentrations, and increased shoot Fe (up to 7.6-fold)
and Al (up to 5.9-fold) accumulation for different genotypes and soils. Manganese- and
167