Effects of variety, year of cultivation and sulphur supply on the accumulation of free asparagine in the grain of commercial wheat varieties

•Widely differing free asparagine concentration in wheat from two harvest years.•Wide range of acrylamide-forming potential (AFP) in 73 commercial wheat varieties.•Eight varieties identified with consistently low AFP, seven of them soft types, but benefit of using a low AFP variety is lost if sulphur supply is inadequate.•Selecting varieties for low AFP solely on the basis of them being soft would be simplistic.•Information on free asparagine concentration should be available at variety launch.

Free asparagine concentration, which is the determining factor for acrylamide-forming potential in cereals, was measured in grain from wheat grown in field trials in the United Kingdom in 2011-2012 and 2012-2013. There were 25 varieties in 2012 and 59 in 2013, with eleven present in both trials. The trials were split-plot, with half of each plot supplied with sulphur and the other half not. The varietal means (mmol per kg) for free asparagine in the sulphur-fed wheat ranged from 1.521 to 2.687 in 2011-2012 and 0.708 to 11.29 in 2012-2013. Eight varieties were identified as having consistently low free asparagine concentration. There was a differential response of varieties to sulphur, and much higher levels of free asparagine in 2012-2013 versus 2011-2012. Given the short commercial lifespan of some wheat varieties, it is concluded that information on free asparagine concentration should be made available when a variety is launched.