DISSERTATION RESEARCH: Evolution and domestication genetics of the mango

芒果最早在4000多年前在印度被驯化。今天，芒果生长在六大洲，是世界上最重要的热带水果之一。面对气候变化和人口增长，农业必须在面对新的和多变的气候条件的同时努力提高作物产量。应对这些压力源的特性，如耐旱性和抗病性，可以通过作物育种项目引入到作物中。虽然有数百种植物经历了驯化，但许多关于驯化对遗传多样性影响的概念都来自于对玉米和水稻等短命作物的研究。这种关注给我们在其他植物物种（如果树）的驯化方面留下了知识空白。在驯化过程中，许多作物失去了遗传多样性，这可能导致可能对农业有用的有益性状在无意中丧失。然而，一些证据表明，长寿的植物，如果树，可能不太容易受到驯化的负面影响。该项目将以最近的努力为基础，通过提供对芒果进化史的基本了解，扩大对非主食作物驯化的科学见解，并将为未来的育种计划奠定基础，以提高其农业品质。在其最初的驯化之后，芒果（芒果科）被分散在整个热带和温暖的亚热带地区。然而，印度芒果的东迁和西迁可能对栽培芒果的遗传结构和多样性产生了显著不同的影响。在向西穿越非洲到达美洲的过程中，印度芒果遭遇了一系列的种群瓶颈，这表明这种作物的遗传多样性只有有限的一部分到达了新大陆。相反，向东扩张到东南亚，使它与超过35种其他芒果属植物接触。形态学证据和初步遗传数据表明，来自这些野生近缘种的基因流可能增强了东南亚籼稻的遗传多样性。本研究将利用双消化限制位点相关DNA （ddRAD）测序技术，对世界各地植物园栽培的192个芒果品种进行遗传多样性、群体分化和杂交研究，其中包括116个已知地理来源的籼稻品种和76个来自其他4个地区栽培的芒果品种。

The mango was first domesticated in India more than 4,000 years ago. Today, mangoes are grown on six continents and are one of the world's most important tropical fruits. In the face of climate change and a growing human population, agriculture must strive to improve crop yields while facing new and variable climatic conditions. Traits to deal with these stressors, like drought tolerance and disease resistance, can be introduced into crops through crop breeding programs. Although hundreds of plant species have undergone domestication, many concepts about the impacts of domestication on genetic diversity have come from research focusing on short-lived crops like maize and rice. This focus has left gaps in our knowledge about domestication in other plant species, such as fruit trees. During the process of domestication, many crops lose genetic diversity, which can result in the unintentional loss of beneficial traits that could be useful for agriculture. However, some evidence that suggests long-lived plants, like fruit trees, may be less susceptible to the negative impacts of domestication. This project will build on recent efforts to expand scientific insight into the domestication of non-staple crops by providing a basic understanding of the evolutionary history of the mango, and will lay the groundwork for future breeding programs to improve its agricultural qualities. Following its original domestication, the mango, Mangifera indica L. (Anacardiaceae), was dispersed throughout the tropics and warm subtropics. However, the eastward and westward migrations of Mangifera indica may have had strikingly different effects on the genetic structure and diversity of cultivated mango. During its journey westward through Africa and on to the Americas, Mangifera indica suffered a series of population bottlenecks, suggesting that a limited amount of the crop's genetic diversity reached the New World. Conversely, eastward expansion into Southeast Asia brought it into contact with more than 35 other Mangifera species. Morphological evidence and preliminary genetic data indicate that the genetic diversity of M. indica in SE Asia may have been bolstered by gene flow from these wild relatives. This research will use double digest restriction site associated DNA (ddRAD) sequencing to investigate genetic diversity, population differentiation, and hybridization in 192 Mangifera accessions cultivated at Botanic Gardens around the world, including 116 M. indica cultivars of known geographic origin and 76 accessions from four other regionally-cultivated Mangifera species.