Protein Concentration of Winter Wheat Varieties in Oklahoma 2021–2022

General Information 

Protein is just one of many attributes that determines end-use quality and marketability of winter wheat. In fact, some millers and bakers would argue that functionality of wheat protein is more important than the quantity of protein. While varietal differences exist, variability in protein among environments is generally much larger. Factors such as nitrogen (N) fertilization and drought stress, for example, can sharply impact final wheat protein concentration. 

 

To reflect these management and environmental impacts on wheat protein concentration, data are reported by variety and location in Table 1. In Table 2, we report the wheat protein concentration by variety as a deviation from the location mean. This allows for easier comparison of wheat protein among varieties across locations. Doublestop CL Plus and Green Hammer, for example, showed positive deviation from the location mean in all of this year’s trials where it was planted, indicating a tendency for above-average wheat protein concentration. Iba, on the other hand, showed a negative deviation from location mean in all of the trials where it was planted, indicating a tendency for lower than average wheat protein concentration. Adequate and timely N fertility as recommended by a recent soil test or sensor-based N management program can help ensure that varieties with lower than average protein produce wheat or four protein within the acceptable range for the end-users. 

 

However, protein quantity should not be considered a barometer for protein quality (i.e., dough strength and functionality), though high protein quantity and quality can occur in the same variety. Doublestop CL Plus is one example. Iba is a prime example of how protein data can sometimes be misleading, as the functionality of the protein in Iba is above average, which can offset lower absolute protein concentration. More information on end-use quality is available in Current Report 2165 Wheat and Flour Quality for Varieties Tested in the 2016 OSU Variety Performance Tests. 

 

 

Procedures 

Approximately 600 g subsamples of wheat grain were collected at harvest from four field replicates of all entries for each OSU Wheat Variety Performance Test. Each test was properly fertilized and managed according to OSU Cooperative Extension recommendations. Additional information on test locations and management practices is available in Current Report 2143 2021-2022 Oklahoma Small Grains Variety Performance Tests online at www.wheat.okstate.edu. Samples were analyzed nondestructively immediately after harvest for wheat protein concentration on a 12% moisture basis, using a Diode Array Near Infrared (NIR) moisture and protein determinator (model DA 7200, Perten Instruments, Sweden). 

 

 

Data Interpretation

At the bottom of each table, the mean and least significant difference (LSD) values are reported. The LSD is a test statistic that aids in determining whether there is a true difference in protein. In this report, one can be 95% confident that the difference between two varieties is real if the difference is greater than the LSD value. Data that is not statistically different is indicated by “NS”. For example, if the LSD value is 1% in a trial where Variety A had 13% protein and Variety B had 10% protein, then Variety A would be considered to have a statistically higher protein. However, if Variety C had 12% protein, then Variety A and Variety C would be considered to have a similar protein. In that same example trial, there is a 5% chance that the 1% protein difference between Variety A and Variety B does not truly exist, but random chance caused the difference. These chance factors may include differences in fertility, moisture availability, and diseases. To aid in visualizing the varieties with the highest protein, values highlighted in gray do not differ statistically from the highest value within a column. 

 

Table 1. Wheat protein concentration (12% moisture basis) of varieties and experimental lines tested in the 2021-2022 Oklahoma Wheat Variety Performance Tests. 

Notes: Protein was adjusted to 12% moisture content. Shaded values are not statistically different from the highest value within a column. NS = not significant. Single-dash "-" = data not available. 

 

The extremely high grain protein concentration values for Cherokee possibly reflect a combination of drought stress and the inability of the NIR machine to precisely measure values above the calibration curve (>17-18%), and thus are not included in this final report. 

 

Table 1. Wheat protein concentration (12% moisture basis) of varieties and experimental lines tested in the 2021-2022 Oklahoma Wheat Variety Performance Tests. (cont'd) 

Notes: Protein was adjusted to 12% moisture content. Shaded values are not statistically different from the highest value within a column. NS = not significant. Single - dash "-" = data not available.

 

 

Table 2. Wheat protein concentration relative to the location mean (expressed as a deviation) for varieties and experimental lines in the 2021-2022 Oklahoma Wheat Variety Performance Tests. 

Notes: Protein was adjusted to 12% moisture content. Shaded values are not statistically different from the highest value within a column. NS = not significant. Single-dash "-" = data not available.

 

The extremely high grain protein concentration values for Cherokee possibly reflect a combination of drought stress and the inability of the NIR machine to precisely measure values above the calibration curve (>17-18%), and thus are not included in this final report. 

 

 

Table 2. Wheat protein concentration relative to the location mean (expressed as a deviation) for varieties and experimental lines in the 2021-2022 Oklahoma Wheat Variety Performance Tests. (cont') 

Notes: Protein was adjusted to 12% moisture content. Shaded values are not statistically different from the highest value within a column. NS = not significant. 

Single- dash "-" = data not available. 

 

 

 

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