This year’s wheat harvest is currently underway across the country after a difficult growing season, with harvest itself being delayed due to intermittent stormy weather. The high levels of rainfall at the start of the growing season meant that less winter wheat could be planted and dry weather in April and May caused difficulties for spring wheat as well. This decline in the wheat growing area has caused many news outlets to proclaim the worst wheat harvest in 40 years and potential bread price rises.
Difficult weather during this year’s growing season. Photo: Joe Oddy
This is also the first wheat harvest in which I have a more personal stake, namely the first field trial of my PhD project; looking at how asparagine levels are controlled in wheat. It seemed like a bad omen that my first field trial should coincide with such a poor year for wheat farming, but it is also an opportunity to look at how environmental stress is likely to influence the nutritional quality of wheat, particularly in relation to asparagine.
The levels of asparagine, a nitrogen-rich amino acid, in wheat grain have become an important quality parameter in recent years because it is the major determinant and precursor of acrylamide, a processing contaminant that forms during certain cooking processes. The carcinogenic risk associated with dietary acrylamide intake has sparked attempts to reduce consumption as much as possible, and reducing asparagine levels in wheat is a promising way of achieving part of this goal.
Asparagus, from which asparagine was first discovered and named.
Previous work on this issue has shown that some types of plant stress, such as sulphur deficiency, disease, and drought, increase asparagine levels in wheat, so managing these stresses with sufficient nutrient supply, disease control, and irrigation can help to prevent unwanted asparagine accumulation. Stress can be difficult to prevent even with such crop management strategies though, especially with environmental variables as uncontrollable as the weather, so it is tempting to speculate that the difficulties experienced this growing season will be reflected in higher asparagine levels; but we will have to wait and see.