Wheat quality means different things to different people, depending on their perspective and their role in the wheat chain. For example, a wheat producer’s conception of what constitutes a good wheat may be radically different from the opinion of a baker working with flour.
The characteristics that impact wheat quality can be loosely categorized into two main groups. The first group of attributes is those that are inherent, i.e. under genetic control. The second group includes those characteristics influenced more by seasonal or site-specific factors.
Some of the traits listed as inherent can also be impacted by seasonal or site-specific conditions. For instance, soil type or depth remain constant from season to season, but will still have an impact on yield or protein content.
The breeders have developed varieties tailored to specific growth environments. For the crop to demonstrate its inherent quality traits, farmers should ensure that they plant the varieties selected for their region and growing conditions.
Cereal quality can be impacted at a number of stages during the production process.
Seeding date – Delayed seeding may result in reduced kernel size; early seeding may result in undesirably low protein concentration and protein quality. These effects are more dramatic in areas facing water-stress.
Seeding rate – Extremely low seed rates can lead to larger grains and very high seed rates can lead to smaller grains and lower milling quality. These effects are intensified by drought, disease, and lodging.
Crop lodging – Early lodging can result in a small kernel, while later lodging will lead to kernel shriveling, and reduced test weight and milling quality.
Nutrient supply – Whether as nutrients already in the soil or as additions of manure or fertilizer, nutrient availability and uptake will certainly impact wheat quality.
Nitrogen application – Generally, earlier nitrogen application produces higher yields and lower protein concentration, whereas later application results in higher protein content and lower yields.
Moisture levels at time of harvest – High moisture can indicate low yields, as the maximum dry weight is not achieved. Low moisture during harvest can damage the crop through cracking and breaking.
Storage – Quality loss during storage is caused by grain deterioration, either through physical/chemical processes (i.e. high humidity) or through biological processes (i.e. pests).
Because wheat differs so much from one class to the next, it is difficult to arrive at an overall definition. The quality of a wheat class is determined by its suitability for a specific final product. For instance, soft wheat is judged by its suitability for the production of cakes, cookies, or crackers.