OSU Deoxynivalenol, DON, Resistance Screening Program-2024

This past year, with support from Ohio Corn and Wheat through the Corn Check Off, we established a pilot corn deoxynivalenol (DON) hybrid susceptibility screening trial. The objective of this project was to identify hybrids with partial genetic resistance to DON. Use these results with caution because this is our first year of data. This trial was conducted at three locations across the state that represent different production regions:  Apple Creek, Bucyrus, and South Charleston. While we had three different environments, the fact that the hybrids vary in maturity means that there is a chance that the weather was not conducive to ear infection and DON production by the fungus Fusarium graminearum during each individual hybrid pollination window. All locations had natural infection across all maturity groups, but to help increase the change of Gibberella ear rot (GER) development, and consequently, DON contamination of grain, we also inoculated plots at Bucyrus and Apple Creek. Since average DON contamination was not significantly different between inoculated and naturally infected plots at these two locations, the results are summarized, and hybrids are compared, by location. With a relative maturity spread of 18 RM, the pollination window at all 3 sites was 3 weeks from the time the first silks emerged until only brown silks were found.

We have been researching several management strategies to reduce grain contamination with this mycotoxin, but less emphasis has been placed on genetic resistance. Results from our previous work with a very small number of hybrids showed that partially resistant hybrids with naturally and consistently lower DON levels are easier to keep low than those that were highly susceptible. A total of 80 hybrids from 8 seed companies were included as part of this screening. While this is only a small subset of the hybrids that are planted in Ohio, the results below not only show the importance of hybrid selection but also can be used to help you begin to select hybrids with natural partial resistance to DON, or at the very minimum, avoid highly susceptible hybrids. With one year of data, we cannot guarantee that the hybrids with low DON this year will always have low DON across all environments. The only thing we can guarantee is that the high-DON hybrids are susceptible. This is an excellent place to start.  

The weather conditions at all locations in 2023 deviated from normal. All locations had below-average rainfall, temperature, and growing degree days. The only time of year that was above average at all locations was the month of August when 0.98-4.87 more inches of rain than the 10-year average fell. The full weather date for the growing season is summarized in Tables 2 through 4 below with full monthly data available at: Ohio Corn Performance Test (osu.edu). Weather conditions during pollination are critical with infection occurring while silks are still wet and relative humidity is >80% with temperatures between 59°F and 86°F.  

Table 1 below summarizes the DON ppm as an average across locations and at each location. DON levels values with an asterisk (*) are not statistically different from the lowest average DON level. The variability among some of the hybrids with high DON levels led to high coefficient of variation and LSD, especially at Bucyrus. A total of 13 hybrids had average DON below 1 ppm (range 0 to 2.4) and 28 hybrids had average DON below 2 ppm (range 0 to 4.1) at all locations. A total of 43 hybrids had average DON below 3 ppm at all 3 locations, but the range of DON for these hybrids was 0-6.5 ppm across all plots at these locations.

Plots were managed for high yield at all locations. At Bucyrus and South Charleston, tar spot was found at low levels in the fields just before tassel. Being overly cautious about damage to the plots, a fungicide was applied at both locations. At Bucyrus, Miravis Neo was applied at tassel emergence. In some of other previous trials, Miravis Neo reduced average DON levels when applied between tassel and green silk. This application may have helped lower DON levels in some of the hybrids that may have had higher natural levels of the toxin if not treated with the fungicide. At South Charleston, Veltyma, a fungicide not known to be effective against DON, was applied. This location also experienced a windstorm just before tassel which resulted in severe goose-necking during the pollination window. 

See full hybrid trial report here.

(Table 1) – DON contamination of 80 hybrids averaged across locations and across plots at each location.

Weather data Planting to Harvest

(Table 2) Bucyrus weather data

Planting date: May 19^th Harvest date: November 16^th

(Table 3) Apple Creek

Planting date: May 26^th Harvest date: December 13^th

(Table 4) South Charleston

Planting date: May 23^rd Harvest date: November 20^th

Thank you to the Ohio Corn Performance Trial and the Paul lab for the management of these plots.