Assessing the role of genetics for improving the yield of Australia’s major grain crops on acid soils

Acid soils (pH <5.0) continue to limit the yields of Australia’s major crops and restrict their cultivation. These soils pose various abiotic stresses that restrict or affect plant growth in different ways. Chief among these stresses is aluminium (Al3+) toxicity, which inhibits root growth. Soil acidification can occur naturally but certain agricultural practices accelerate the process. The most effective management practice for slowing and reversing acidification is the application of lime (calcium carbonate). Liming has increased over the last 25 years but it can take several years to ameliorate subsoil acidity and the application rates in some areas remain too low to avoid further acidification. If left unmanaged, acidification will degrade agricultural land and cause larger yield losses in the future. Crops that are better adapted to acid soils are important resources because they help to maintain production while amelioration efforts continue. Significant genotypic variation for acid-soil tolerance has been reported in wheat, barley and pulse species and improvements to yield are likely by pyramiding the optimal genetic loci controlling this trait through breeding. Further increases in production might also be possible with wider crosses to related species and through genetic engineering. This review assesses the potential of genetics and biotechnology for increasing the yields of Australia’s major grain crops on acid soils.