Popcorn [ (L.) var. Everta] is an important field crop in the Midwestern United States. However, hailstorms are a major threat to ensuring high yield because of their effects on leaf photosynthesis, pollination, and stalk lodging. A multi-state study spanning six site-years (2020–2023) was conducted in two locations (Ohio and Nebraska) to determine how defoliation intensity at different stages affects yield loss in popcorn and compare these losses with current values in the National Crop Insurance Service (NCIS) Corn Loss Instructions. At each location the study was conducted in a randomized complete block design with four replicates. The treatments consisted of the combination of four levels of leaf loss (25, 50, 75 and 100 % leaf blade area removal) imposed at five developmental stages: V8 (10-leaf), V13 (15-leaf), VT, R2, and R4. The evaluated traits were plant population, grain yield, stalk lodging, and 100-kernel weight. All evaluated traits were affected by defoliation, except plant population. The treatments 100 % defoliation at VT and R2 stages were the most damaging in terms of grain yield reduction, number of ears per plant and 100-kernel weight for both locations. In Ohio, the greatest stalk lodging was observed at 100 %-R2 and in Nebraska, at 75 %-VT. For both locations, the actual yield losses in the defoliated treatments were lower than values currently listed in the NCIS Popcorn Leaf Loss Chart. These results indicate leaf loss chart values should be updated to accurately reflect yield losses from popcorn defoliation events. This evaluation did not impose damage to stalks (e.g., bruising) or to plant whorls as may be expected in natural events. Future research should incorporate other forms of plant damage such as those described to provide a better emulation of hail damage.

中文翻译：

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落叶水平和时间影响美国中西部的爆米花产量特征


爆米花 [ (L.) 变种。 Everta]是美国中西部的一种重要大田作物。然而，冰雹由于影响叶片光合作用、授粉和茎倒伏，是确保高产的主要威胁。在两个地点（俄亥俄州和内布拉斯加州）进行了一项跨越六个站点年（2020-2023）的多州研究，以确定不同阶段的落叶强度如何影响爆米花的产量损失，并将这些损失与国家农作物保险中的当前值进行比较服务 (NCIS) 玉米损失说明。在每个地点，研究均以随机完整区组设计进行，并进行四次重复。这些处理包括在五个发育阶段施加的四种叶片损失水平（25%、50%、75% 和 100% 叶片面积去除）的组合：V8（10 叶）、V13（15 叶）、VT、R2、和R4。评估的性状包括植物种群、谷物产量、茎倒伏和百粒重。除植物种群外，所有评估的性状均受到落叶的影响。 VT 和 R2 阶段 100% 落叶处理对于两个地点的谷物产量、每株果穗数和 100 粒重量的降低影响最大。俄亥俄州在 100%-R2 时观察到最大的茎倒伏，在内布拉斯加州则在 75%-VT 时观察到最大的茎倒伏。对于这两个地点，落叶处理的实际产量损失低于 NCIS 爆米花叶损失图表中当前列出的值。这些结果表明，应更新叶片损失图表值，以准确反映爆米花落叶事件造成的产量损失。该评估没有像自然事件中预期的那样对茎（例如擦伤）或植物轮生造成损害。 未来的研究应该纳入其他形式的植物损害，例如所描述的那些，以更好地模拟冰雹损害。