ABSTRACT Background: Maize in Mexico exhibits great genetic diversity, maintained by traditional practices of indigenous and non-indigenous communities, the same practices that have led to crop diversification over centuries. As one of the main staple crops worldwide, safeguarding the genetic diversity of maize is paramount to food security. Aims: This study evaluated the genetic diversity and population structure of traditionally cultured maize landraces in a rural seasonal agricultural community in Veracruz, Mexico, in order to learn how traditional practices shape these landraces, and propose strategies for their preservation. Methods: We analysed 118 individual maize samples belonging to five morphotypes (white, yellow, black, red and mottled) with eight microsatellite markers. Results: We encountered high genetic diversity, according to expected heterozygosity (He = 0.61). However, inbreeding coefficient and gene flow values suggested the existence of assortative mating, which causes low genetic differentiation. Population structure analysis identified three genetic pools, independent of grain colour. These findings suggest that all morphotypes belong to the same population, which is sub-structured due to assortative mating and gene flow related to local agronomic management. Conclusions: Current management practices in this community could lead to genetic erosion. In order to preserve diversity, wider regional seed exchange and selection for morphological diversity could be implemented.

中文翻译：

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墨西哥一个偏远农村社区传统种植混养中的玉米遗传多样性：对管理和可持续性的影响

摘要背景：墨西哥的玉米表现出巨大的遗传多样性，由土著和非土著社区的传统做法维持，几个世纪以来，这些做法已导致作物多样化。作为全球主要的主粮作物之一，保护玉米的遗传多样性对粮食安全至关重要。目的：本研究评估了墨西哥韦拉克鲁斯农村季节性农业社区中传统养殖的玉米地方品种的遗传多样性和种群结构，以了解传统做法如何塑造这些地方品种，并提出保护策略。方法：我们用 8 个微卫星标记分析了 118 个属于五种形态型（白色、黄色、黑色、红色和斑驳）的玉米样品。结果：我们遇到了高遗传多样性，根据预期杂合性（He = 0.61）。然而，近交系数和基因流值表明存在分类交配，导致低遗传分化。种群结构分析确定了三个遗传库，与谷物颜色无关。这些发现表明，所有形态型都属于同一种群，由于与当地农艺管理相关的分类交配和基因流，它们是亚结构的。结论：该社区当前的管理实践可能导致遗传侵蚀。为了保护多样性，可以实施更广泛的区域种子交换和形态多样性选择。种群结构分析确定了三个遗传库，与谷物颜色无关。这些发现表明，所有形态型都属于同一种群，由于与当地农艺管理相关的分类交配和基因流，它们是亚结构的。结论：该社区当前的管理实践可能导致遗传侵蚀。为了保护多样性，可以实施更广泛的区域种子交换和形态多样性选择。种群结构分析确定了三个遗传库，与谷物颜色无关。这些发现表明，所有形态型都属于同一种群，由于与当地农艺管理相关的分类交配和基因流，它们是亚结构的。结论：该社区当前的管理实践可能导致遗传侵蚀。为了保护多样性，可以实施更广泛的区域种子交换和形态多样性选择。