Effect of Seed Treatment on Plant Stands and Yield in Winter Wheat

In 2010, higher than normal levels of Fusarium head blight were detected in many winter wheat fields in Manitoba. Questions arose around the use of seed treatments in winter wheat production and their role in managing fusarium-infected seed. Since seed treatments can protect germinating seed and young seedlings from seed-borne and soil-borne pathogens, a 2-year trial was undertaken to look at the effect of seed treatments on seed lots with varying levels of Fusarium graminearum.
Experimental Design
Two seed lots of CDC Falcon were used with different levels of Fusarium graminearum. There were 7 seed treatments applied to each seed lot in addition to an untreated 'check'. The entries included Cruiser Maxx Cereals, Cruiser Maxx Cereals Proseed, Gemini, Raxil WW, Raxil MD, an experimental product from BASF and an experimental product from Bayer CropScience. Trials were located at Arborg, Beausejour, Carberry, Carman, Melita, Portage, Roblin, Stonewall and Winnipeg. Site cooperators measured plant stands in the fall and spring and yield to help determine if there are any differences between seed treated and untreated in the two seed lots.
Preliminary Results
Currently, yield data is only available for the locations of Arborg, Portage, Stonewall, Roblin, and Beausejour (see Table 1). Preliminary results indicate there was no significant difference in yield between the various seed treatments and the untreated check. However, at the Roblin and Beausejour sites, there was a significant difference between the various seed treatments.
Table 1: Yield Response to Seed Treatments at Various Manitoba Location (2011)
Seed Treatment
 2011 Yield by Location (Bushels per Acre)
Arborg Portage Stonewall Roblin Beausejour
Untreated 84 113 95 84 93
Cruiser Maxx Cereals 83 110 92 84 92
Cruiser Maxx Cereals Proseed 86 110 90 85 91
Gemini 78 110 94 82 92
Raxil MD 82 116 93 90 88
Raxil WW 86 110 96 87 93
BASF-Experimental 83 109 95 90 93
Bayer-Experimental 86 118 94 93 94
CV 6.8 5.2 3.4 6.4 2.1
LSD - - - 7 2
Sign Diff No No No Yes Yes
For the 5 locations, only Arborg, Portage and Stonewall had both spring and fall plant stand data (not presented). In the fall, only the Portage site saw significant differences between seed treatments where all treatments had a significant improvement over the untreated check. In the spring, only the Arborg site saw a significant difference in plant stand counts between the seed treatments. Although there was an effect of seed treatment on plant stands at these two sites, this did not translate into an effect on yield.
Keep in mind these are only preliminary results and data for all sites were not available at time of publication. As well, Viterra is currently measuring thousand kernel weight and protein on composite samples to help determine impact on quality. The 2011/12 growing season will be the second year of this trial and as additional results become available over the next year, updates will be provided.
Final Thoughts
The first course of action should always be to secure top quality seed to maximize crop production and profitability. If you suspect issues with disease pressure, test your seed. Commercial seed laboratories can determine the percentage and species of Fusarium. Since studies from AAFC have shown that fusarium damaged kernels can affect stand establishment and yield, it is important to not use seed with extremely high levels. For seed lots with lower disease pressure, use of seed treatments is recommended as a best management practice. But keep in mind that seed treatments do not bring back to life dead seeds and seed treatments will not prevent fusarium head blight from developing later in the season from stubble-born inoculums where Fusarium species are already present.
Thank you to Winter Cereals Manitoba Inc., Bayer CropScience, Syngenta, BASF and MCVET for their financial support. Thank you to our site contractors PESAI, WADO, PCDF, CMCDC, ICMS, and the University of Manitoba and to Viterra for quality analysis.