Abstract: The stem traits（including stem length，stem diameter，dry weight，dry weight per unit length of the aboveground 3rd to 5th internodes，stem puncture strength and stem crushing strength）of 150 improved American maize inbred lines（with Zheng 58 as the control）planted during 2023—2024 were analyzed.Correlation analysis，cluster analysis，principal component analysis（PCA），and grey relational analysis were comprehensively applied to evaluate lodging resistance，and screen inbred lines with high lodging resistance，so as to provide theoretical support for the breeding of lodging‐resistant maize varieties.The results showed that among the 150 maize inbred lines，the dry weight of the aboveground 3rd internode exhibited the richest variation，with the largest variation coefficients of 46.51% and 39.52% in two years，respectively.Correlation analysis revealed that stem crushing strength was extremely significantly positively correlated with stem puncture strength；both stem puncture strength and stem crushing strength were significantly or extremely significantly positively correlated with the aboveground 3rd internode stem length，as well as stem diameter，dry weight，and dry weight per unit length of the aboveground 3rd to 5th internodes.Cluster analysis indicated that the maize inbred lines were divided into 4 clusters，among which cluster Ⅰ and cluster Ⅱ had high stem puncture strength and stem crushing strength.Principal component analysis showed that the cumulative contribution rates of the first two principal components in 2023 and the first three principal components in 2024 reached 82.51% and 84.57%，respectively.A total of 9 inbred lines（XM082，XM026，XM059，XM107，XM084，XF001，XM119，XM117，XM040）ranked in the top 20% of the 150 inbred lines in terms of comprehensive lodging resistance score in both 2023 and 2024，and their comprehensive lodging resistance scores were significantly higher than that of the control Zheng 58.Grey relational analysis demonstrated that the dry weight，dry weight per unit length and stem diameter of the aboveground 3rd to 5th internodes had relatively high relational degrees with the comprehensive lodging resistance score，which could be used as important indicators for the identification of maize lodging resistance.

Key words: Maize, Lodging resistance, Stalk traits, Principal component analysis, Grey relational analysis

摘要： 对2023—2024年种植的150份美系改良自交系（以郑58为对照）的茎秆性状（地上第3—5节茎长、茎粗、干质量、单位长度干质量及茎秆穿刺强度、茎秆压碎强度）进行分析，采用相关性分析、聚类分析、主成分分析、灰色关联度分析综合评价抗倒能力，筛选出高抗倒伏的自交系，为抗倒伏玉米品种的选育提供理论支撑。结果表明，150份玉米自交系的地上第3节干质量变异最丰富，2 a变异系数均最大，分别为46.51%、39.52%。相关性分析结果表明，茎秆压碎强度与茎秆穿刺强度呈极显著正相关，茎秆穿刺强度、茎秆压碎强度均与地上第3节茎长及地上第3—5节茎粗、干质量和单位长度干质量呈显著或极显著正相关。聚类分析结果表明，玉米自交系被分为4个类群，类群Ⅰ、Ⅱ具有茎秆穿刺强度、茎秆压碎强度高的特点。主成分分析结果表明，2023年前2个主成分、2024年前3个主成分的累计贡献率分别达82.51%、84.57%；2023年和2024年，抗倒能力综合得分均位列150份自交系前20%的自交系共有9份（XM082、XM026、XM059、XM107、XM084、XF001、XM119、XM117、XM040），抗倒能力综合得分均远高于对照郑58。灰色关联度分析结果表明，地上第3—5节干质量、单位长度干质量、茎粗与抗倒能力综合得分的关联度较大，可作为玉米抗倒性鉴定的重要指标。

关键词: 玉米, 抗倒伏, 茎秆性状, 主成分分析, 灰色关联度分析