Late-maturity α-amylase (LMA) is a genetic defect in wheat (Triticum aestivum L.) involving the production of high pI αamylase in the aleurone during grain filling and maturation, resulting in grain with an unacceptable low Hagberg Falling Number. Grain with a Falling Number below the receival threshold (typically 300 s) will be downgraded, resulting in financial losses to the farmer. To protect the Australian wheat industry, wheat cultivars with a high risk of LMA expression do not receive a milling classification in Australia. A long-term solution requires breeding of low LMA wheat varieties. Since LMA expression is under both genetic and environmental control this will require (1) elucidation of the genetics of LMA to enable marker-assisted breeding, and (2) a better understanding of the induction of LMA by the environment (low temperature), to improve the phenotyping procedure. Several QTL for LMA expression have been identified, with a major locus located on the long arm of chromosome 7B. The gene underlying this locus has now been identified, as well as several haplotypes of this gene that confer high and low LMA expression. The “Green Revolution” gibberellin-insensitive semi-dwarfing genes Rht-B1b and Rht-D1b have also been shown to reduce expression of LMA under certain conditions. The existence of genetic repressors of LMA has also been suggested and is currently under investigation. A cooltemperature-shock during the middle of grain development is the most efficient method of inducing LMA known to date and therefore used in the existing LMA phenotyping protocols. The sensitivity to LMA-induction by cool-shock during grain development has now been characterized in detail for genotypes with and without Rht semi-dwarfing genes, aiding accurate timing of the cool-shock. It was also found that rather than a cool-shock, cool temperatures per se can induce LMA, which if found to be reliable would allow for a simplified LMA screening system.