Most Popular Wheat Varities in the Alberta Peace Sown at Various Rates

by María Angélica Ouellette PhD

Several varieties of wheat were sown at different seeding rates to evaluate plant height, protein content, yield, thousand kernel weight and test weight. It was expected that differences in varieties of either cereal as well as sowing rates based on number of plants per square foot might influence the outcome of grain production as well as influence the other wheat parameters previously mentioned. For this project AAC Brandon, AAC Redwater, AAC Viewfield and AAC Wheatland were chosen as the most popular wheat varieties among growers and subjected to four seeding rates such as 25, 30, 35 and 40 plants per squared foot.

Materials and methods

The experiments were conducted in Alberta by SARDA Ag Research in Falher, Peace Country Beef and Forage Association in Fairview, Mackenzie Applied Research Association in Fort Vermilion and North Peace Applied Research Association Research in North Star in the growing season of 2022. Figure 1 through 5 show the weather and precipitation recorded during the growing season.

Experimental set-up

Trial experiments were set up as a random complete block design with four replicates. All research was conducted in the research farms of all associations except SARDA Ag Research, whose treatment plots were set in High Prairie. Plot areas varied were 0.0013 High Prairie, 0.0022 acres in Fairview, 0.0018 acres in Fort Vermilion and 0.0032 acres in North Star. Seeding occurred in May 25, May 24, June 10 and May 22, 2022, in High Prairie, Fairview, Fort Vermilion and North Star. Seeding depth was 0.75 inches in High Prairie and Fairview whereas in Fort Vermilion and North Star, wheat was sown 1.5 inches below surface. In Fort Vermilion seeding occurred on May 31st, but emergence was poor. Moreover, due to a logistics error, AAC Redberry was re-seeded on June 8 as seed was confused with a lentil variety (CDC Redberry) instead of that of wheat.

Fertilizer

In High Prairie, wheat was fertilized with an NPKS blend (101-25-35-5) at 50 pounds per acre. In Fairview the fertilizer was a blend of NPKS at 304 pounds per acre pounds per acre. Fertilization in Fort Vermilion consisted of a mixture of urea, MAP (11-52-0), potash (0-0-60) and Sulphur ME15 at 22.74,2.5, 2.2 and 38,6 pounds per acre respectively. In North Star wheat was fertilized with urea and S15 (13-33-0-15S), each at 100 pounds per acre.

Maintenance

Maintenance sprays varied across sites as well. In High Prairie, glyphosate (RoundUp WeatherMax) mixed with a pre-packaged blend of pyraflufen-ethyl and bromoxynil (Conquer II) was broadcasted pre-seed at 0.67 and 0.242 L acre-1 respectively on May 26. Applications in-crop at the same site were MCPA and pinoxadem (Axial) at 0.189 and 0.5 L acre-1 respectively as well as a mixture of halaxfem and florasulam (Paradigm) at 10 g acre-1 on June 15. At Fairview, maintenance spray performed on June 24 consisted of pre-mixed fluoroxypyr and MCPA (Prestige XL) at 0.81 L acre-1. Glyphosate (RoundUp) was broadcasted pre-seed and in crop in Fairview at 0.67 L acre-1. In addition, a pre packaged mix of pyrasulfotole and bromoxynil (Infinity) was used for weed management in wheat at 0.33L acre-1. Wheat in North Star was maintained with saflufenacil (Heat LQ) and glyphosate (RoundUp) on May 20 and fluoxypyr, clopyralid and MCPA (Esteem) on June 14.

Harvest

Harvest was conducted on September 16, 24, 26 and 27, 2022 in High Prairie, Fairview, Fort Vermilion and North Star, Alberta. Harvested areas varied from 0.0013 to 0.0019 acres in High Prairie, from 0.0018 to 0.0022 acres in Fairview, 0.0018 acres in Fort Vermilion and 0.0032 acres in North Star.

Statistics

Data was computed as an analysis of variance with three fixed effects and three random effects. Fixed effects were wheat variety and seeding rate as well as its interaction. Random effects were research location site, replicates and its interaction. Parameters for analysis included plant height, protein content, thousand kernel weight (TKW) and test weight. Parameters like emergence and stand count were not included as only two out of the four sites recorded these values. To procure normality, and independence among data research points taken, thousand kernel weight and test weight were transformed to the square power.

Results Height

Wheat stands were affected by an interaction effect between variety and seeding rate. As such, taller in AAC Redberry seeded at 40 plants foot-2 compared to stands found in plots seeded at 40 plants foot-2 from the AAC Viewfield variety (P=0.0198). In fact, AAC Redberry wheat stands at 40 plants foot-2 was 11% greater than average of all wheat varieties at the same seeding rate (P=0.0022) and AAC Viewfield at 40 plants foot-2 was 12% shorter than the average of all other varieties under the same seeding rate (P=0.0003). Individually, wheat variety plays a role in plant height (P=0.0018) but not seeding rate (P=0.5590). According to wheat varieties, AAC Viewfield wheat in total, grows 6% shorter than the other varieties (P=0.0013). Stand heights found in AAC Brandon at 30 plants foot-2, AAC Redberry and AAC Wheatland at 35 plants foot-2 as well as AAC Wheatland at 40 plants foot-2 were statistically similar to those heights found in wheat seeded at 40 plants foot-2 from AAC Redberry variety. In contrast, AAC Viewfield at any rate can grow as tall as AAC Brandon at 40 plant foot-2 and AAC Redberry and AAC Wheatland at 25 and 30 plants foot-2. Short stands from AAC Viewfield were likely as a response to heavy intraspecific competition would rather switch to use its energy for reproductive development rather than height during the vegetative stage. Contrary to AAC Redberry, where stand growth is promoted as a response to intraspecific competition.

Protein content

Protein content was affected by the Interaction between these two main effects (P=0.0.0043). In fact, AAC Brandon wheat sown at 25 plants foot-2 and AAC Redwater sown at 30 plants foot-2 had 6% (P=0.0003) and 5.5% (P=0.0006) respectively more protein content than other varieties sown at the same rates (P=0.0003). AAC Viewfield seeded at 25 and 30 plants foot-2 had 4.2 (P=0.0145) and 5% (P=0.0061) less protein content respectively than the other wheat varieties sown at the same rates.

Thousand kernel weight, test weight and yield

Wheat varieties had significantly different TKWs (P<0.0001). In fact, AAC Brandon and AAC Redberry had 5.4% and a 1% heavier TKWs respectively, than average values from the other varieties. On the other hand, AAC Viewfield and AAC Wheatland had 5% and 2% lighter TKWs respectively, in comparison to average values from other varieties. Test weight was the same across all varieties (P=0.5053) and seeding rates (P=0.3779), as well across the interaction values of these two main effects (P=0.2544). Yield in contrast to TKW and test weight varied depending on wheat varieties (P=0.0001). AAC Redberry was 7.2% less yield than average of other wheat varieties (P=0.0008) whereas AAC Viewfield had 8% more yield that average value of the other wheat varieties (P=0.0001). This may support the argument that short stems in AAC Viewfield are likely because energy from the plant is directed towards seed development rather than vegetative growth, possibly at an earlier stage than other wheat varieties. In contrast, energy that individuals from the AAC Redwater variety is directed to stem growth rather than seed development.

Conclusion

In conclusion, the interaction effect between wheat variety and seeding rate only influenced main stem height. Seeding rate influenced content of protein in wheat, where lowest and greatest protein content values were found at 25 and 30 plants foot2 respectively. Wheat varieties was the factor that impacted most parameters. Thousand kernel weight and yield were affected depending on the wheat variety being seeded. As such, AAC Viewfield was found to have the lightest TKW and the most yielding wheat variety. Finally, no matter the wheat variety and how much seed are placed in the ground on a plant per squared foot basis, test weight has will be the same regardless.

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