Ontario Grain Farmer December 2021/January 2022

14 PLANT GROWTH REGULATOR (PGR) use on intensively managed wheat has become an avidly discussed topic over the past few years; and duringmany conversations, there are more questions than answers. Dr. Dave Hooker, University of Guelph, Joanna Follings, Ontario Ministry of Agriculture, Food and Rural Affairs, Dr. Joshua Nasielski, University of Guelph, and Peter Johnson, Real Agriculture, have set out to answer the questions of developing effective strategies for managing lodging risk in cereals, and to determine the fit of PGRs within this approach — using combinations of cultivars, nitrogen (N) rates, N timings (one vs. split), and N sources, with and without a PGR. The three-year project began in 2021. Initial results look promising to give farmers a better understanding of when and how to use PGRs. PGRs have been around for a long time and are widely used in other countries. In the past, for Ontario farmers, PGRs were available, but small windows of application limited the uptake. When minimum residue limits were set for a new PGR in 2018, that is when PGRs really gained momentum. By 2020, there was a large interest in PGRs, especially amongst farmers who intensively manage wheat and those who have livestock who have dealt with lodging for a long time. 2021 saw many doing strip trials in their fields, which is a great way to learn and adds to the pool of information, along with this new research Plant growth regulators REDUCE LODGING IN INTENSIVELY MANAGED WHEAT Laura Ferrier that is headed by a very knowledgeable group of Ontario scientists. When speaking with some of the key collaborators on the PGR project, Follings shared that “farmers need to look at what the problem is that they are trying to solve. It’s a decision-making process the grower needs to go through on whether or not they need a PGR.” QUESTIONS Some questions Follings says that farmers need to ask are: What is the lodging risk? Along with, is it a farm that has high amounts of manure applied? Was it early planted, with lots of growth from a great fall season? What is the soil type, topsoil depth, and is the farmer pushing nitrogen (N) and sulphur (S) rates and at what timing? Is the nitrogen applied in one application or is it split applied? What variety is planted? Even the PGR application timing needs to be considered. It is important to look at some of the contributing factors that increase lodging risk a little more. For Follings, there were some huge varietal responses seen, the most she has seen in her career to date. “Some varieties, it was clear that they should have a PGR, some others may not see an advantage,” she notes. What is really interesting to Johnson is that the research team, “learned so much this year by the interaction of different varieties to weather conditions — genetics by environment.” In general, if the farmer is selecting a variety with a low lodging score and doing a split application of N, in most cases the wheat can be managed, have good yields, and not need a PGR. Agronomy