The origins of plant domestication in the upper Madeira River basin in lowland South America

在10000年前之后不久，美洲和世界其他几个主要中心开始了植物驯化和农业发展，这是人类最关键的成就之一。古植物学和分子遗传学的最新进展为理解这一关键变化最初发生的时间、地点、方式和原因开辟了新的途径。例如，对现存种群的系统发育和系统地理研究往往可以确定野生祖先种群，从而确定每种驯养动物的地理发源地，从而将考古学家引导到有限的区域进行调查和挖掘。越来越多的遗传、生物地理和考古植物学数据现已将亚马逊地区确立为世界上最重要的植物驯化中心之一。最近的遗传和生物地理学研究表明，亚马逊西南部季节性森林和稀树草原的过渡边缘，包括马德拉河流域上游，可能是几种主要美国作物驯化的摇篮，包括木薯(Manihot Esculenta)、花生(Arachim Subgaea)、桃棕榈树(Bactris Gasipaes)、古柯(Erythroxella Coca)、辣椒(Capsicum Baccatum)、红薯(Bixa Orellana)和烟草(Nicotina TabToba)(Clement et al.2010年；Piperno和Pearsall，1998年)。尽管是南美洲低地最重要的驯化中心，但到目前为止，还没有跨学科项目记录这些重要作物在其原产地的驯化情况。为了解决这个问题，我们建议组织两个研讨会和进行初步研究活动，以计划、编写和提交一个为期3-5年的国际跨学科项目，该项目整合了分子遗传学、植物生物地理学、考古学、考古植物学和古生态学。该项目的主要目标将是：i)调查主要亚马逊作物的历史，包括木薯、桃树、辣椒和红木；ii)重建早期农业的背景；iii)调查人类对亚马逊西南部马德拉河上游环境影响的时间和性质。这些目标分别建立在由Iriarte和Clement协调的两个独立的研究方向上：巴西南部阿劳卡里亚森林景观变化的古生态学和考古学(AHRC-FAPESP)和普鲁斯-马德拉河(ERC)，以及亚马逊本地作物的起源、扩散和系统地理(Fapeam、Fapeam-Aird、CNPq、FAPESP)。该项目恰逢其时，结合最先进的技术来解决植物驯化和农业发展的复杂性。对作物起源的研究得益于微化石植物学技术的改进，特别是从用于处理植物的石器残留物中提取的淀粉颗粒，这使得考古植物学家能够记录热带地区的根茎作物，这些热带地区的大型植物遗骸(可见的种子和水果遗骸)保存较差(Piperno 2011)。古生态技术将有助于重建马德拉河上游晚更新世至全新世的植被历史，特别是第一批作物驯化的自然环境和植物组合。将特别强调人类如何以及何时开始改变他们的环境，利用火灾历史来重建自然和人类造成的过程之间的关系。遗传分析可以确定开始现代作物驯化的第一批选择的野生种群，以及追踪这些驯化中心之外的扩散。

Plant domestication and the development of agriculture began shortly after 10,000 years ago in the Americas and several other primary centres around the world, and was one of humankind's most pivotal achievements. Recent advances in palaeobotany and molecular genetics have opened new avenues for understanding when, where, how, and why this crucial change first came about. For example, phylogenetic and phylogeographic studies of extant populations can often identify the wild ancestral population and thus the geographic cradle of origin for each domesticate, pointing the archaeologists to a limited area for survey and excavation. A growing body of genetic, biogeographical, and archaeobotanical data has now established Amazonia as one of the most important centres of plant domestication in the world. Recent genetic and biogeographic studies show that the transitional fringe of seasonal forests and savannahs in SW Amazonia, which encompass the upper Madeira River Basin, were probably the cradle of the domestication of several major American crops, including manioc (Manihot esculenta), peanuts (Arachis hypogaea), peach palm (Bactris gasipaes), coca (Erythroxylum coca), chilli peppers (Capsicum baccattum), annatto (Bixa orellana), and tobacco (Nicotina tabacco) (Clement et al. 2010; Piperno and Pearsall 1998). Despite being the most important centre of domestication in lowland South America, until now no interdisciplinary projects have documented the domestication of these important crops in their cradle of origin. To address this issue, we proposed to organise two workshops and conduct preliminary research activities to plan, write and submit a 3-5 yr international interdisciplinary project integrating molecular genetics, plant biogeography, archaeology, archaeobotany and paleoecology. The main objectives of the project will be to: i) investigate the history of major Amazonian crops including manioc, peach palm, chilli peppers and annatto; ii) reconstruct the context of early agriculture; and iii) investigate the timing and nature of human impact on the environment in the upper Madeira River, SW Amazonia. These objectives build on two previously separate lines of research coordinated by Iriarte and Clement: paleoecology and archaebotany of landscape transformations of the Araucaria forests of southern Brazil (AHRC-Fapesp) and the Purus-Madeira interfluve (ERC), and the origin, dispersal and phylogeography of native Amazonian crops (Fapeam, Fapeam-AIRD, CNPq, Fapesp), respectively.The project is well-timed to combine state-of-the-art techniques to address the complexity of plant domestication and the development of agriculture. Research on crop origins are benefiting from the refinement of microfossil botanical techniques, in particular starch granules retrieved from the residues of stone tools used to process plants, which are allowing archaeobotanists to document root crops in tropical regions exhibiting poor preservation of macrobotanical remains (visible remains of seeds and fruits) (Piperno 2011). Palaeoecological techniques will help reconstruct the Late Pleistocene through Holocene vegetation history of the upper Madeira River and, in particular, the natural environment and plant associations in which the first crops were domesticated. Particular emphasis will be given to how and when humans began to alter their environments, using fire history to reconstruct the relation between natural- and human-caused processes. Genetic analysis can identify the wild populations from which the first selections were derived to start the domestication of our modern crops, as well as to trace dispersals out of these centres of domestication.