Ontario Corn Committee Hybrid DON Testing in 2018

Figure 1. Gibberella ear rot - Red/pink mould which often begins on ear tip (OMAFRA)


This article was written by Dave Hooker and Albert Tenuta, on behalf of the Ontario Corn Committee

Although 2018 was very challenging to growers and the rest of the corn industry, it presented an opportunity to compare hybrids for DON accumulation across several locations of the Ontario Corn Performance Trials. The main purpose of the OCC study was to provide growers with an indication of a hybrid’s relative risk for accumulating the mycotoxin DON, and to provide a framework for future performance testing.

OCC Locations and Data Collection
A total of 1,225 grain corn samples were collected while machine harvesting plots for OCC Tables 4 (82 hybrids at Belmont, Exeter, Ilderton) and Table 5 (54 hybrids at Ridgetown and Tilbury) locations. There were 30 hybrids common across both Tables. Each hybrid was replicated 3 times at each location; therefore, each hybrid was represented by 9 samples across locations in OCC Table 4, and 6 samples across OCC Table 5 locations. Samples were dried and then analyzed for DON by SGS Laboratories (Guelph) using the ELISA method. Tables of results from the OCC Hybrid Corn Performance Testing, and the agronomic practices used at each location can be found in the trial management section ofthe 2018 OCC Corn Performance Report at www.gocorn.net.

Hybrids silked between late July and the first week of August at all locations. Frequent rains and high humidity during silking and grainfill of all hybrids across all locations resulted in favorable environmental conditions for natural Gibberella ear rot infection and DON accumulation.

Interpretation of the Rating Table
Hybrid differences for DON were statistically highly different (P<0.0001) within Table 4, Table 5 and across hybrids common to both Tables 4 and 5. The OCC decided to simplify the presentation of results by using a colour-coded (available on www.gocorn.net) or gray-scale rating for hybrids within OCC Table 4, OCC Table 5, and with those hybrids common across both Tables. The hybrids in the Rating Table were sorted based on their CHU rating.

As expected, there were no hybrids resistant to DON accumulation (i.e., zero ppm). In this gray-scale version of the Rating Table, zero ppm is illustrated in white. Hybrids were coded in light gray (lower than average DON) to dark gray (higher than average DON) to black (highest DON) based on the range of DON concentrations in the Rating Table columns (OCC Table 4, OCC Table 5 or 30 hybrids common to Tables 4 and 5). Hybrids with no rating indicates that the hybrid was not tested at the locations represented in each column or OCC Table.

Some statistics of the DON concentrations within each Table are presented in the footnote of the Rating Table. A hybrid shaded with a different shading across columns in the Rating Table may simply indicate variability in hybrid across locations, samples and/or analysis.

The OCC is grateful to Grain Farmers of Ontario (GFO) for their leadership, GFO and OMAFRA for the financial support to analyze the grain samples for DON, and to University of Guelph/OMAFRA research technicians for collecting the samples (Jonathan Brinkman, Ken VanRaay, Cheryl Van Herk, Brooke Jones and a very big thanks to Scott Jay for coming out of retirement to assist).

Contact information
Dr. David Hooker, University of Guelph, Email: dhooker@uoguelph.ca
Albert Tenuta, OMAFRA, Email: albert.tenuta@uoguelph.ca
David Morris, OCC Secretary, Email: dtmorris@rogers.com