Investigating Hybrid Interactions with Nitrogen and Foliar Fungicides
IPNI-2010-CAN-ON30
23 Feb 2012
2011 Annual Interpretive Summary
Corn Hybrid Interactions with Nitrogen and Foliar Fungicides, 2011
Growers have shown interest in corn hybrid differences in response to applications of fungicide and N. Fungicides can potentially improve N use efficiency by delaying leaf senescence and enhancing the “stay-green” physiological mechanism. This project aims to determine the potential for yield improvement through exploitation of hybrid-fungicide-N interactions. Field trials implemented at three sites in southwestern Ontario compared six hybrid pairs (triple-stacked with corn rootworm resistance versus Roundup-Ready-only isolines) at five N rates with two fungicides (Headline and Proline) and a non-fungicide control.
Results in 2010 from two of the three sites showed strong evidence of hybrid-by-N interactions, and some evidence of hybrid-by-fungicide interactions. The highest yield of 224 bu/A was produced by the Pioneer hybrid 35F44 (a triple-stack) with Headline fungicide and N applied at 120 lb/A. The triple-stacked trait in general, however, did not have much influence on N use efficiency. The fungicides interacted only slightly with N rate, tending to increase both optimal rates and yields by about 2%. Dry growing conditions near the end of the season may have limited the expression of the stay-green trait.
Good results were obtained in 2011 from all three sites. Despite a rainy spring that delayed planting until June, peak yields at all 3 sites exceeded 200 bu/A, approaching 250 bu/A at one of the sites. The study provided clear evidence that yield response to N varied among corn hybrids, but was not correlated to the corn rootworm resistance or ‘triple-stack’ trait. Responses to fungicide application averaged 3 to 4 bu/A and did not depend on N rate. Analysis of plant and grain uptake and concentrations remains to be completed. Further studies exploring ways to improve yield along with NUE will build on the foundation of findings from this study. ON-30