The genetic characteristics of maize (Zea mays L.) germplasm are helpful to understand their genetic diversity and heterotic group, as well as provide a reference for germplasm improvement and GWAS. A total of 241 maize inbreds including tropical, subtropical, and temperate maize, were selected from the global maize germplasm in the study. Genetic diversity, population structure, genetic relationship, and LD were analyzed using the Affymetrix SNP56K chip. Finally, 20,586 high-quality SNP markers were screened out which detected a total of 41,172 allelic variants among materials, the average gene diversity was 0.3779 and the average PIC was 0.3002. There were greater genetic differences between different germplasm sources, the genetic diversity of China & USA maize was higher than that of CIMMYT & Thailand maize. Based on model analysis, cluster analysis, and PCA, a consistent population structure was got that the materials were firstly divided into tropical & subtropical maize and temperate maize; then, the latter was furtherly divided into three subgroups named SS, NSS, and TSPT, and the remaining inbreeds were classified into Mixed groups. The results were consistent with domestic major results as well as their pedigree information. The LD decay distance of temperate maize was greater than tropical & subtropical maize. This study further confirmed that there exists population stratification among tropical, subtropical, and temperate maize germplasm, but the specific stratification results may be different by using different materials, markers, and analysis methods. In addition, the genetic difference between temperate maize and tropical & subtropical maize is certainly great, the latter will continue to play an important role in maize breeding in China.

玉米（Zea mays）的遗传特性L.) 种质有助于了解其遗传多样性和杂种优势群，为种质改良和GWAS提供参考。研究共从全球玉米种质中选择了热带、亚热带和温带玉米等241个玉米自交系。使用Affymetrix SNP56K芯片分析遗传多样性、种群结构、遗传关系和LD。最终筛选出20586个优质SNP标记，共检测到材料间等位基因变异41172个，平均基因多样性为0.3779，平均PIC为0.3002。不同种质来源间遗传差异较大，中美玉米遗传多样性高于CIMMYT和泰国玉米。基于模型分析、聚类分析和 PCA，得到了一致的种群结构，材料首先分为热带和亚热带玉米和温带玉米；然后，后者进一步分为SS、NSS和TSPT三个亚群，其余近交系分为混合群。结果与国内主要结果及其系谱信息一致。温带玉米的LD衰减距离大于热带和亚热带玉米。本研究进一步证实了热带、亚热带和温带玉米种质之间存在种群分层，但具体分层结果可能因使用不同的材料、标记和分析方法而有所不同。另外，温带玉米与热带亚热带玉米的遗传差异当然很大，