Corn School: Protecting grain quality in the disease nursery

Why is there an irrigated corn crop growing in the middle of the University of Guelph’s Ridgetown campus?

On this episode of the RealAgriculture Corn School, host Bernard Tobin takes a trip into the research maze to get a look at what happens in this corn misting nursery. Tobin first encounters University of Guelph associate professor Dr. Dave Hooker. He notes that the nursery was set up in 2019, following the gibberella ear rot and mycotoxin epidemic that swept though the Ontario corn crop in 2018.

Hooker says the corn industry needed to assess commercial hybrids for resistance, tolerance and susceptibility to gibberella. Seed companies and growers also needed information to make hybrid choices that could help defend against the disease. He adds that agronomic practices, fungicides and application technology can also help manage the disease — these are also assessed.

In the nursery, hybrids are misted with water to produce a favourable environment for the disease. Each plant is then inoculated by hand with the disease pathogen that produces deoxynivalenol (DON) mycotoxins.

In 2022, 60 hybrids were tested in the nursery using three different planting dates to help account for environmental factors and variability. Once the data from this year have been analyzed, it will build upon a growing body of evidence used to identify hybrids, or groups of hybrids, that are susceptible to mycotoxin accumulation. The objective is to also identify hybrids that are more resilient and show less mycotoxin accumulation. Hooker says it takes a lot of work to assemble and crunch the data, but he is hopeful a new report will be available to growers before the calendar turns to 2023.

Tobin then travels to another part of the nursery where OMAFRA plant pathologist Albert Tenuta and a team of collaborators are looking for future disease defences as they test new corn germplasm for genetics that can deliver tolerance and resistance to gibberella ear rot and DON production.

In the video, Tenuta looks at potential winners and losers in the fight against the disease. He shares how germplasm and inbreds are evaluated and identified, as well as the time and effort required to get desirable disease genetics into high-yielding, adapted corn hybrids.