Ecological processes during the origins of agriculture in the Fertile Crescent

肥沃的新月地区的农业起源是人类历史上的一个关键时刻，导致了西亚和欧洲文明的繁荣。考古证据表明，在1万年前的新石器时代，人们开始在肥沃的新月地带种植野生植物。通过种植和管理这些植物，第一批农民无意中推动了驯化作物的进化。考古证据还表明，在同一时期，早期农民放弃了许多由早期狩猎采集社会收集、加工和储存的野生谷物物种。我们对新石器时代农业起源的两个重要问题感兴趣。1.在人类栽培和管理下，什么生态机制能够驱动野生植物驯化特性的进化？2.在从采集到栽培的过渡过程中，同样的生态机制是否能够负责将广泛的野生谷物物种缩小到一小群作物祖先？通过找到这些问题的答案，我们将更好地了解农业是如何开始的，以及今天的驯化作物是如何形成的。我们的主要假设是，作物祖先具有预先适应人类环境的特征，包括耕种和管理的田地。当人们第一次开始定居和种植植物时，这些特殊的物种因此在肥沃、密集的耕地环境中茁壮成长，偶尔会受到同时驯养的动物的干扰。我们进行了一系列实验，用温室盆栽植物来验证这一假设。我们已经有了许多发现。首先，当在密林中种植作物时，野生近缘作物的产量比其他野生谷物物种高，但当植物单独种植时就不是这样了。这支持了这样一种观点，即作物祖先可能预先适应了密集的耕地。其次，受干扰后，作物近缘物种的产量比其他野生物种更高，相当于动物的放牧。因此，在向农业过渡的过程中，它们的产量受到早期畜群动物的影响较小。最后，作物野生近亲的谷物产量与种子大小相关，因此农民对更高产量的选择将推动种子大小的增加，这是一个关键的驯化试验。在这个项目中，我们希望通过在土耳其肥沃的新月会进行田野研究来跟进这些发现。首先，调查作物野生近缘植物和其他野生谷物物种在自然气候和土壤条件下的行为。其次，观察农业开始前收集的野生谷物物种的分布和收获特征，调查这些物种如何在自然栖息地种植植物。我们的工作对于了解农业是如何在新石器时代肥沃的新月地区开始的，也对于解决未来对农业未来可持续性的担忧是重要的。作物野生近缘关系对现代作物育种非常重要，因为它们包括对病虫害的各种防御，以及更有效地利用土壤养分的机制，包括与土壤真菌的共生。通过探索作物野生近缘物种的多样性，我们还将学习更多关于如何在未来更可持续地种植我们的现代作物。

The origin of agriculture in the Fertile Crescent was a pivotal moment in human history, leading to flourishing civilizations through Western Asia and Europe. Archaeological evidence shows that people began to cultivate wild plants across the Fertile Crescent during the Neolithic, 10,000 years ago. By cultivating and managing these plants, the first farmers unintentionally drove the evolution of domesticated crops. Archaeological evidence also shows that, during the same period, early farmers abandoned many of the wild grain species that had been gathered, processed and stored by earlier hunter-gatherer societies.We are interested in two important questions about the Neolithic origins of agriculture. 1. What ecological mechanisms are capable of driving the evolution of domestication characteristics in wild plants under human cultivation and management? 2. Could the same ecological mechanisms be responsible for narrowing down a broad spectrum of wild grain species to a small pool of crop progenitors during the transition from gathering to cultivation? By finding the answers to these, we will better understand how agriculture began, and how today's domesticated crops came into being. Our overarching hypothesis is that crop progenitors have characteristics that pre-adapt them to anthropogenic environments, including cultivated and managed fields. When people first began to settle and cultivate plants, these particular species therefore thrived in the fertile, densely packed environments of cultivated fields, with occasional disturbance from the animals that were domesticated at the same time.We have carried out a range of experiments to test this hypothesis with plants grown in pots in glasshouses. We have made a number of discoveries. First, crop wild relatives are higher yielding than other wild grain species when grown in dense stands, but not when plants are grown individually. This supports the idea that crop progenitors may be pre-adapted to densely packed cultivated fields. Secondly, crop relatives yield more highly than other wild species after disturbance, equivalent to grazing by animals. Their yields would therefore have been less impacted by early herd animals during the transition to agriculture. Finally, grain yield in crop wild relatives is correlated with seed size, so that selection by farmers for greater yield would drive increased seed size, a key domestication trait.In this project, we would like to follow up these discoveries with field studies in the Fertile Crescent of Turkey. Firstly, to investigate the behavior of crop wild relatives and other wild grain species under natural climate and soil conditions. Secondly, to look at the distribution and harvest characteristics of the wild grain species gathered before agriculture began, investigating how these grow plants in their natural habitats. Our work is important for understanding how agriculture began in the Fertile Crescent during the Neolithic, but also for addressing future concerns about the future sustainability of agriculture. Crop wild relatives are important for modern crop breeding, because they incorporate a diverse array of defences against pests and diseases, and mechanisms for more efficient use of soil nutrients including a symbiosis with soil fungi. By exploring the diversity of crop wild relatives, we also stand to learn more about how to grow our modern crops more sustainably in future.