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Does PGR have an effect on the quality of wheat and flour?

Plant growth regulators (PGRs) are a popular crop protection product used to reduce plant height and improve standability in wheat for growers but does it impact the quality of end-use wheat and flour? Cereals Canada along with Manitoba Crop Alliance led the research on a two-year project to assess the quality of wheat, flour and end-products of Canadian red spring wheat varieties including Canada Western Red Spring Wheat and Canada Northern Hard Red treated with a plant growth regulator.  

While PGRs have been tested to ensure they do not compromise safety, agronomics, or disease resistance, minimal testing has been completed to determine the effects PGR have on the quality of wheat and flour. Supporting the value chain, Cereals Canada looked at the impact on quality.  

Partnering on research projects like the PGR study shows the strong collaboration of the industry and how Cereals Canada continues to support agriculture research. From the wheat kernel to the loaf of bread, Cereals Canada staff has the resources to examine the effects and impact for our farmers and customers. “We encourage the use of all science-supported tools to grow a strong profitable crop for farmers and we also work to ensure that the end products meet the needs of the customers,” says Dean Dias, Chief Executive Officer.  

All samples were graded to understand which downgrading factors were present and how this could potentially impact wheat, flour and end-product quality. Wheat samples were milled into a straight grade flour on a laboratory scale mill.  This flour was subsequently used to produce pan bread using a long-time fermentation baking process. The wheat and flour of each sample were analyzed to understand its quality. 

The analysis included the following tests listed below.

  • Wheat: test weight, protein content, falling number, wet gluten, gluten index), ash content, particle size index (PSI).  
  • Lab milling: clean, temper, lab mill, prepare straight grade flour and calculate flour extraction rates.  
  • Flour: protein content, ash content, wet gluten, gluten index, colour, starch damage, Amylograph peak viscosity, Farinograph, Extensograph.  
  • End-product: bake using a long-time fermentation baking process and assess end-product quality (specific volume, crumb structure, etc.). 

“The quality differences of wheat varieties treated with and without PGR over two years were minimal suggesting that PGR application had little or no effect on wheat, flour or end-product quality, “states Elaine Sopiwnyk, Vice-President Technical Services. “Variety appeared to have more of an effect on quality than the use of a PGR. The presence of downgrading factors, such as hard vitreous kernels (HVK) and fusarium damage (FUS DMG) likely contributed to some of the differences observed.” 

Plant growth regulators are approved for use and can be another tool for farmers to help manage growing a sustainable wheat crop. “This is important as it has the potential to allow the wheat to maintain its grade and avoid downgrading which would impact wheat quality and lessen the economic returns to the grower,” says Lori-Ann Kaminski, Research Program Manager with Manitoba Crop Alliance.  

The full report can be reviewed here.