Evolution of Clonally-propagated Crops Under Human Influence: The Example of the Andean Tuber Crop Oxalis tuberosa

营养繁殖作物在养活世界方面发挥着巨大的作用，但我们对它们与种子繁殖作物的进化和保护需求的不同之处知之甚少。关于克隆生长如何与人类对作物的选择和传播相互作用，从而影响植物驯化和作物进化，人们知之甚少。本研究以安第斯块茎作物“OCA”--块茎紫花苜蓿为研究对象，研究人类交换网络如何在地理上分布这种作物的无性系，以及它们如何影响传统自给自足农业中的克隆多样性。具体地说，该项目比较了不同地区OCA的多样性以及与其他克隆植物的差异，并使用空间统计方法分析了秘鲁安第斯山脉OCA的克隆和遗传结构模式。DNA指纹分析(荧光AFLP)可以区分长相相似的块茎是否是遗传克隆。这类数据还将OCA与野生草本植物进行比较，以检验关于OCA多染色体组(多倍体)起源的假设(基于先前的DNA序列数据)。培训讲习班和秘鲁学生参与研究将建立保护安第斯地区丰富农业生物多样性的国际能力。为了更好地获取信息，将以英文和西班牙文在科学论文和演示文稿以及非技术性出版物中传播成果。菲尔德博物馆、密歇根州立大学和秘鲁利马的国际土豆中心之间的合作，互惠地建设机构能力。社会效益包括改进保护克隆作物多样性的战略，以及增加对其驯化的了解。由于在传统农业中对任何作物的克隆分布知之甚少，这一结果不仅对保护OCA的多样性具有重要意义，而且将有助于我们更好地理解人类对其他营养繁殖作物的影响。

Vegetatively-propagated crops play an enormous role in feeding the world, but we understand poorly how they differ from seed-propagated crops in their evolution and needs for conservation. Little is known about how clonal growth interacts with selection and dispersal of crops by humans to influence plant domestication and crop evolution. This research uses the Andean tuber crop "oca," Oxalis tuberosa, to study how human exchange networks distribute clones of the crop geographically and how they affect clonal diversity in traditional subsistence agriculture. Specifically, this project compares the diversity of oca among different localities and to other clonal plants, and uses spatial statistics to analyze patterns of clonal and genetic structure of oca across the Peruvian Andes. DNA fingerprinting (fluorescent AFLP) distinguishes whether similar-looking tubers are genetic clones. The same kind of data also compares oca to wild Oxalis species to test hypotheses (based on previous DNA sequence data) about the origins of oca's multiple chromosome sets (polyploidy).Training workshops and involvement of Peruvian students in the research will build international capacity for protecting the rich agricultural biodiversity of the Andean region. To improve access to information, results will be disseminated, in both English and Spanish, in scientific papers and presentations as well as in non-technical publications. Collaboration between The Field Museum, Michigan State University, and the International Potato Center in Lima, Peru, reciprocally builds institutional capacity. Societal benefits include improving strategies to conserve the diversity of clonal crops and increasing understanding of their domestication. Because so little is known about clonal distributions of any crop in traditional agriculture, the results will not only be important to conserve oca's diversity, but will improve our understanding of the human influence on other vegetatively-propagated crops.