Performance of Blends Vs. Blend Components of Soft White Winter Wheat Varieties in Washington.

Annually soft white winter wheat production in Washington State exceeds 1.3 million acres with up to 20% seeded with blended varieties. Justifications for blending are: more stable grain yield, disease mitigation, and improved test weight and protein content of the grain. This study investigates the benefits of growing blended varieties and if this practice is warranted. Data collected by the Washington State University Variety Testing Program was utilized. Results from soft white winter wheat trials from 21 locations for 2006-2012 were summarized. All trials were RCBD or Alpha-Lattice designs with 3 replications. Grain yield, test weight and protein content for blended varieties and individual blend components were compared. Grain yield of blends significantly exceeded the average yield of blend components in only 27 of the 454 observations (6%), while blends yielded below components in 19 observations (4%). Blends out yielded the best blend component only 5 times (1%) and performed significantly below the best blend component in 85 observations (19%). Test weight of blends was significantly higher than the average of components in 28 of 450 total observations (6%) and significantly below the average in 20 cases (4%). Blends significantly exceeded test weight of the best component in only 9 observations (2%), and performed below the best component in 129 cases (29%). Protein content of blends was significantly higher than component average in 18 of 454 observations (4%) and significantly lower in 26 observations (6%). Blends’ protein content exceeded the best component in 6 cases (1%) and was significantly lower in 86 cases (19%). Grouping data by precipitation zones did not change performance results. This study shows that growing blended soft white winter wheat varieties in Washington does not result in improved grain yield performance, test weight, or protein.