Abstract: In order to determine the suitable planting density of summer foxtail millet in Henan Province,five main cultivars (Yugu 18,Jigu 20,Baogu 22,Yugu 23 and Yugu 28) were used to evaluate the effect of different planting densities (3.0×10⁵ ,4.5×10⁵,6.0×10⁵ and 7.5×10⁵plants/ha) on the characters of top three leaves and panicle.The results showed that the width and length of top three leaves,spike length,spike diameter,single spike weight and grain weight per spike decreased with the increase of planting density,plant height,1 000-grain weight and milled millet percentage did not change significantly with the increase of planting density,but there were slight differences among the cultivars.With the increase of planting density,on the whole,there were no significant differences in the traits of top three leaves and panicle under low planting densities (3.0×10⁵—4.5×10⁵plants/ha) or high planting densities(6.0×10⁵—7.5×10⁵ plants/ha);however,these traits changed significantly when the planting density increased from 4.5×10⁵ to 6.0×10⁵ plants/ha.Grain yield increased first and then decreased with the increase of planting density,Yugu 18,Jigu 20,Baogu 22 and Yugu 23 had the highest yield under the planting density of 6.0×10⁵ plants/ha,and Yugu 28 had the highest yield under the planting density of 4.5×10⁵ plants/ha.Correlation analysis showed that there were positive correlations between the traits of top three leaves(width and length of leaves)and spike traits(spike length,spike diameter,single spike weight and grain weight per spike).According to the comprehensive analysis,the recommended planting density of summer foxtail millet cultivar is 4.5×10⁵— 6.0×10⁵ plants/ha.

Key words: Planting density, Foxtail millet, Top three leaves, Panicle traits, Phenotypic plasticity

摘要： 为了探明河南省夏谷品种适宜的种植密度，以生产上常用的5个夏谷品种豫谷18、济谷20、保谷22、豫谷23、豫谷28为试验材料，设置30、45、60、75万株/hm² 4个种植密度，分析不同种植密度对顶三叶和穗部性状的影响。结果表明，顶三叶宽、长及穗长、穗粗、单穗质量、穗粒质量均随着种植密度增加呈明显降低的趋势，株高、千粒质量、出谷率总体上变化不显著，品种间存在轻微差异。在低种植密度（30万～45万株/hm²）或者高种植密度（60万～75万株/hm²）条件下，随着种植密度增加顶三叶、穗部性状的差异总体上均不显著；而种植密度从45万株/hm²增加到60万株/hm²，顶三叶和穗部性状总体上变化明显。随着种植密度的增加，5个品种的产量均先升高后降低，豫谷18、济谷20、保谷22、豫谷23等4个品种在60万株/hm²种植密度下的产量最高，豫谷28在45万株/hm²种植密度下产量最高。相关性分析表明：顶三叶性状（叶宽和叶长）与穗部性状（穗长、穗粗、单穗质量、穗粒质量）呈正相关。综合分析，推荐夏谷品种适宜种植密度为45万～60万株/hm²。

关键词: 种植密度, 谷子, 顶三叶, 穗部性状, 表型可塑性