Improving Nitrogen Efficiency of Meadow Bromegrass and Orchardgrass

Project Title

Modulating Nitrogen Responses in Forage Grasses for Improved Nitrogen use Efficiency, Yield, and Grazing Tolerance


Charitha Jayasinghege (AAFC Agassiz)

Stacy Singer, AAFC, Lethbridge, Alberta Shabtai Bittman and Derek Hunt, AAFC, Agassiz, British Columbia

Status Project Code
In progress. Results expected in April, 2024 POC.21.21


Giberellin (GA) is a plant hormone that regulates growth and reproduction. GA encourages the plant to grow tall but GA suppresses a second gene (called NGR5) that encourages tillering. High GA levels might make the plant less responsive to nitrogen fertilizer-induced tillering. Previous work in rice has shown that semidwarf varieties with lower GA levels and increased NGR5 levels have better tillering, yield and nitrogen use efficiency.


  • To evaluate if gibberellin regulates N-induced tillering in meadow bromegrass and orchardgrass

What they will do

These researchers want to see if modulating GA can affect tillering, yield and N requirements in meadow bromegrass and orchardgrass. They will grow orchardgrass and meadow bromegrass under three different N levels and 5 different levels of plant growth regulators (PGRs) that increase or inhibit GA. They will evaluate forage yield, tiller numbers and the ratio of seed-bearing to leaf-bearing tillers.


This specific experiment will use PGRs, but PGRs are often not cost effective for use in forages. What the use of PGR’s will tell us in this study is if selecting for higher NGR5 gene expression may be a way to develop forage varieties that tiller more and yield better but don’t have higher N requirements.