Effect of plant growth regulator application on yield and quality of malting barley

This Barley Research Cluster project was funded by Alberta Barley in collaboration with the Atlantic Grains Council, the Brewing and Malting Barley Research Institute, Rahr Malting and the Western Grains Research Foundation via the AgriInnovation Program.

Project lead: Dr. John O’Donovan, Research Scientist
Agriculture and Agri-Food Canada

Start Date: April 2013

End Date: March 2018

Alberta Barley’s contribution:  $38,631
Total funding from other partners: $275,343

Benefits for barley farmers:
Assuming no significant negative effects, PGR application could reduce lodging, increase yield and possibly increase the amount of barley acceptable for malting. Growers would then have an important tool to reduce lodging and increase yield.

Summary:
Plant growth regulators (PGR) can be a very cost-effective method of reducing the incidence of lodging, which can cause barley yield losses of up to 80 per cent. However, little research has been conducted in Western Canada on their effects on malting barley. This project will assess the risks and/or benefits associated with applying PGRs to mitigate lodging and associated quality and yield loss of malting barley.

Results:
This objective of the project was to study the effects on the agronomic and grain quality after applying PGR’s chlormequat, trinexapac and ethephon on malting barley in order to mitigate lodging. This project identified benefits and risks to using plant growth regulators in western Canadian through the trial being conducted at 5 locations over 3 years (15 site-years). This project will benefit producers by determining whether or not PGR applications were useful in malting barley.  If they were not useful they could save barley farmers money.  If they were useful it provides a new tool for producers.

The field portion of the project was completed in 2016.  Data have been analyzed and summarized and presented at extension events.  A scientific manuscript has been submitted for publication to the Canadian Journal of Plant Science.

Results indicate that overall the ability of the PGRs to mitigate lodging was limited although they were quite successful in reducing height. Trinexapac and ethephon were most successful at reducing height. However, they also had negative effects on agronomic and pre-malt quality measurements like days to maturity and percent plumpness. Chlormequat did not reduce lodging when averaged across sites.  Trinexapac increased yield across site-years but was inconsistent among individual site-years. Ethephon increased the number of tillers per plant, while ethephon and trinexapac increased days to maturity, and reduced kernel weight and percent plump kernels.

Unfortunately, while positive effects of plant growth regulator applications were observed, they were limited and inconsistent.  The observed negative effects on days to maturity and pre-malt quality were more consistent across and within site-years. This indicates the plant growth regulator applications tested may have limited benefit and may actually increase quality risks in western Canada, and would not be recommended for western Canadian malt barley producers based on this study.