Conditions potentially affecting corn ear formation, yield, and abnormal ears: a review

Authors: ORTEZ, OSLER - University Of Nebraska; MCMECHAN, JUSTIN - University Of Nebraska; HOEGEMEYER, THOMAS - University Of Nebraska; CIAMPITTI, IGNACIO - Kansas State University; NIELSEN, ROBERT - Purdue University; THOMISON, PETER - The Ohio State University; Abendroth, Lori; ELMORE, ROGER - University Of Nebraska

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2022
Publication Date: 7/4/2022
Citation: Ortez, O., Mcmechan, J., Hoegemeyer, T., Ciampitti, I., Nielsen, R., Thomison, P., Abendroth, L.J., Elmore, R. 2022. Conditions potentially affecting corn ear formation, yield, and abnormal ears: a review. Crop, Forage & Turfgrass Management. 8(2). Article e20173. https://doi.org/10.1002/cft2.20173.
DOI: https://doi.org/10.1002/cft2.20173

Interpretive Summary: Within corn fields across the Midwest, some ears will always have deformities and when the frequency is high enough, this causes concern to field agronomists and farmers. Questions arise concerning the cause and whether it was due to an uncontrollable, environmental incident or from a farm-level decision that impacted ear formation. If poor ear formation is due to decisions controlled by the farmer, identifying the causes can minimize re-occurrence in following years, potentially resulting in more stable and higher yields. This paper provides a literature review describing the physiological and managerial reasons behind problematic ear formation and is presented so that scientists and stakeholders can better diagnose the cause.

Technical Abstract: Abnormal ear development in corn (Zea mays L.) has been reported for more than 100 years. More recently, in 2016, widespread abnormal multiple ears per stalk node (herein termed as multi-ears), barbell-ears, and short-husks were reported in cornfields located in the western and central US Cornbelt (Kansas, Nebraska, Iowa, and Illinois), Eastern Colorado, and the Texas Panhandle region. Little was known about the underlying causes for these abnormalities. We provide a literature review examining conditions potentially affecting corn ear formation, yield, and abnormal ears. Many environmental and physiological responses may contribute, but specific questions still exist, such as what factors specifically trigger abnormal ears and when that happens. Abnormal ears appear to be formed due to stress (biotic or abiotic) conditions such as extreme weather events (e.g., drought, heat, wind, flooding, hail, freezing), limited solar radiation, and response to plant growth regulators. The accumulation of these effects (stress and response to growth regulators) can result in the abortion of primary ears and the development of secondary abnormally developed ears, which has been a hypothesis for the last fifteen years. Whether or not primary ear abortion is one of the factors remains a valid question. Abnormal ears can be understood as the result of an ‘expression triangle’: susceptible genetics (G), conducive environmental conditions (E), and favorable practices (M). Together, these factors can interact and cause the abortion of primary ears, develop abnormal ears at lower stalk nodes, and result in lower yields.