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

无性繁殖作物在养活世界方面发挥着巨大的作用，但我们对它们在进化和保护需求方面与种子繁殖作物的区别知之甚少。对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，我们知之甚少。本研究利用安第斯块茎作物“oca”，Oxalis tuberosa，研究人类交换网络如何在地理上分布该作物的无性系，以及它们如何影响传统自给农业的无性系多样性。具体而言，本项目比较了不同地区和其他无性系植物的oca多样性，并利用空间统计分析了秘鲁安第斯山脉oca无性系和遗传结构的模式。DNA指纹识别（荧光AFLP）可以区分外观相似的块茎是否为基因克隆。同样的数据还将oca与野生Oxalis物种进行比较，以测试关于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的农业生物多样性的国际能力。为了改善获取信息的机会，将以英文和西班牙文在科学论文和简报以及非技术出版物中传播研究结果。菲尔德博物馆、密歇根州立大学和秘鲁利马的国际马铃薯中心之间的合作相互促进了机构能力的建设。社会效益包括改进保护无性系作物多样性的策略和增加对其驯化的了解。由于对传统农业中任何作物的无性系分布知之甚少，因此该结果不仅对保护oca的多样性很重要，而且将提高我们对人类对其他无性繁殖作物的影响的理解。

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.