Emily Robinson

Corn ( Zea mays L.) yields have increased in the United States since the 1930s and in other parts of the world since the 1950s and 1960s because of improvements in agricultural management and genotypes. Despite these increases, production concerns still exist. In July 2016, abnormal ear development (multi‐ears per node, barbell‐ears, and short‐husks) was reported in cornfields that extended from the Texas Panhandle to eastern Colorado and east through Kansas, Nebraska, Iowa, and Illinois. Surveys in Nebraska farmer fields revealed significant productivity losses due to the issues, but little was known about the underlying causes. A research study was conducted in four Nebraska fields during the 2018 and 2019 growing seasons. The research investigated the effects of hybrids, environments, seeding rates, and their interactions on abnormal ears. Eight hybrids, eight environments, and five seeding rates were studied. About 63,500 plants were individually assessed at or after the dent stage (R5). Grain yield ranged from 4.3 to 20.1 Mg ha −1 . In 2018, about 5% of ears were abnormal; in 2019, about 11%, if combined, about 8%. Higher‐yielding hybrids were associated with lower percentages of abnormalities. Hybrids, environments, and seeding rates influenced the occurrence of abnormal ears. In most cases, abnormal ears had lower heights in the canopy, suggesting that primary ear loss may be a factor. The results reinforced the overriding hypothesis that ear abnormalities result from environmental, genetic, and management interactions. Depending on the environment, selecting certain hybrids with optimum seeding rates could help mitigate the occurrence of abnormal ears.