This study describes the genetic diversity and the population structure of 66 popcorn landrace collections in a recently discovered microcenter of maize (Zea mays L.) diversity in southern Brazil. Furthermore, we elucidate their phylogenetic relationships with a diverse panel of 575 popcorn populations from 18 countries of American Continent. The germplasm, representing distinct landraces, was genetically characterized as population bulks using single nucleotide polymorphism markers (SNPs). Five main groups were identified for the popcorn germplasm of the southern region of Brazil. This pattern was associated with phenotypic diversity in grain shape and color. The germplasm of the American Continent was structured in nine groups associated with geographical region with significant differences in terms of genetic diversity and expansion capacity or popping expansion (the formation of large flakes after the kernels explode in response to heating). The popping expansion pattern of the American groups displayed a North-South geographical continuum, in which the average values increased with geographical distance from the center of origin in Mexico. The highest averages were obtained for the Lowland groups of South America. These results raise two hypotheses: the first one is the possibility of a continuous evolution of this characteristic, which is popcorn did disperse North - South, but interbreeding with local varieties drove up the diversity of the gene pool, and at the same time allowed more efficient selection on the trait of expansion capacity. The second is the possibility of a second domestication event of Zea mays ssp. mays L., in South America, which would assume an independent origin of popcorn, but not an independent domestication of maize. Both hypotheses would be based on popcorn populations brought from Mexico by human migrations. The germplasm collected in the microcenter of diversity in southern Brazil, most of them originated in the Lowlands of South America, a part of germplasm established phylogenetic relationships closer to the popcorn populations of Brazil collected in the last century. The study contributes to improved understanding of the origin and phylogenetics of this maize group and as such to conservation of those valuable genetic resources and future breeding efforts. This is valuable genetic research which led to better insight into grouping and dispersion of studied genotypes in the target region, but also its place vis-à-vis origin and migration of popcorn genotypes in South America in general.

这项研究描述了最近发现的玉米微中心（玉米）中66种爆米花地方品种的遗传多样性和种群结构。L.）巴西南部的多样性。此外，我们通过与美洲大陆18个国家/地区的575个爆米花种群的不同群体来阐明它们的系统发育关系。使用单核苷酸多态性标记（SNP），代表不同地方品种的种质在遗传上被表征为种群种群。针对巴西南部地区的爆米花种质确定了五个主要类别。这种模式与谷物形状和颜色的表型多样性有关。美国大陆的种质结构分为与地理区域相关的9个组，在遗传多样性和扩展能力或爆裂扩展（籽粒因加热而爆炸后形成大薄片）方面存在显着差异。美洲群的爆发式扩张模式显示出一个北南地理连续体，其中平均值随着距墨西哥原点中心的地理距离的增加而增加。南美低地群体的平均值最高。这些结果提出了两个假设：第一个是这种特性可能持续进化的可能性，爆米花确实分散了南北，但是与本地品种的杂交推动了基因库的多样性，同时又允许更多有效选择扩张能力的特征。第二是第二次驯化事件的可能性 南美低地群体的平均值最高。这些结果提出了两个假设：第一个是这种特性可能持续进化的可能性，爆米花确实分散了南北，但是与本地品种的杂交推动了基因库的多样性，同时又允许更多有效选择扩张能力的特征。第二是第二次驯化事件的可能性 南美低地群体的平均值最高。这些结果提出了两个假设：第一个是这种特性可能持续进化的可能性，爆米花确实分散了南北，但是与本地品种的杂交推动了基因库的多样性，同时又允许更多有效选择扩张能力的特征。第二是第二次驯化事件的可能性Zea mays ssp。梅斯L.，在南美，它将假设爆米花的独立来源，但没有玉米的独立驯化。两种假设都将基于人类迁移从墨西哥带来的爆米花种群。在巴西南部的多样性微中心收集的种质，大多数起源于南美洲的低地，种质的一部分建立了与上个世纪巴西收集的爆米花种群更近的系统发育关系。该研究有助于增进对该玉米群体的起源和系统发育的了解，从而有助于保护这些宝贵的遗传资源和今后的育种工作。这是一项有价值的遗传研究，可让您更好地了解目标区域中已研究基因型的分组和分布，