RESEARCH-PGR: The Genetics of Highland Adaptation in Maize

第1部分：非技术摘要玉米起源于大约1万年前，位于墨西哥西南部的一个炎热、干燥、低海拔地区。尽管玉米后来在全球范围内传播，如今拥有全球最广泛的16种主要农作物，但玉米在寒冷中的表现仍然很差。然而，不同地区的农民确实在海拔12,000英尺的凉爽潮湿的山区种植玉米。该项目将确定使玉米适应高海拔的基因变化。研究人员将在高、中、低三个地点进行田间试验，比较高海拔地区和附近低地地区的玉米品种的农艺和遗传性状。这些实验将揭示高海拔适应的基础基因，并将测量基础适应的遗传变化的重复性。此次调查的结果将为高海拔和高纬度(如美国玉米带)地区抗寒玉米品系的开发提供参考。关于如何在高原条件下发生适应的洞察也可以更广泛地应用于使玉米适应其他环境条件。该项目将促进学术界和产业界以及美国和墨西哥之间的合作，为来自这些国家的学生、研究人员和农民创造大量互动和分享专业知识的机会。第2部分：技术摘要植物适应当地环境的遗传基础仍然缺乏特征，尽管它与作物改良和区域气候有关。该项目旨在评估玉米(Zea Mays)的环境适应性，重点是野生和驯化玉米种群对高海拔环境的适应。高地和低地环境在包括温度和降水在内的许多特征上不同，玉米对这些环境的适应涉及到与农艺相关的表型。第一个目标是利用由墨西哥和南美玉米开发的作图群体、天然混合的teosinte群体(即野生玉米)和由行业合作者捐赠的两个导入系群体来确定适应性状的数量性状基因座。这将使控制不同地理区域、不同海拔和包括美国优质玉米种质在内的多种遗传背景的高原性状的基因座进行比较。第二个目标是通过研究玉米和特罗辛特的适应性导入以及低地和高地玉米基因表达的差异，来研究选择的群体遗传学证据。第三个目标是通过对导入系的表型和转录水平的评估来描述适应性倒位多态的功能后果。这项基础研究将与外联活动相辅相成，包括表型讲习班，以展示高通量田间数据收集方法、学生交流和与墨西哥一个育种中心联合举办的农民田间展览。

Part 1: Non-Technical abstract Corn originated approximately 10,000 years ago in a hot, dry, low-elevation region of southwest Mexico. While it has since spread globally and today has the greatest global geographic breadth of 16 staple crops, corn continues to perform poorly in the cold. However, farmers in various regions do cultivate corn in cool, wet mountainous regions as high as 12,000 ft above sea level. This project will identify the genetic changes that allowed corn to adapt to high elevations. The investigators will compare agronomic and genetic traits of corn varieties sampled at high elevation with those from nearby lowland regions in field experiments conducted at high, middle, and lowland sites. These experiments will reveal the genes underlying high-elevation adaptation and will measure the repeatability of the genetic changes underlying adaptation. Results from this investigation will inform the development of cold-hardy corn lines for high-elevation and high-latitude (e.g. U.S. Corn Belt) regions. Insight as to how adaptation occurred in highland conditions can also be applied more broadly to adapting maize to other environmental conditions. This project will foster collaboration between academics and industry and between the United States and Mexico, creating numerous opportunities for students, investigators, and farmers from these countries to interact and share expertise.Part 2: Technical abstractThe genetic basis of plant adaptation to local environments remains poorly characterized, despite its relevance to crop improvement and regional climate. This project seeks to evaluate environmental adaptation in maize (Zea mays), with focus on adaptation to high elevation environments in wild and domesticated populations of maize. Highland and lowland environments differ in a number of features including temperature and precipitation, and maize adaptation to these environments has involved agronomically relevant phenotypes. The first objective is to identify quantitative trait loci for adaptive traits using mapping populations developed from Mexican and South American maize, a naturally admixed population of teosinte (i.e., wild maize) and two populations of introgression lines donated by industry collaborators. This will enable the comparison of the loci controlling highland traits in distinct geographical regions, across elevations, and in multiple genetic backgrounds including elite US maize germplasm. The second objective is to investigate population genetic evidence of selection through studies of adaptive introgression in maize and teosinte, and divergence in gene expression between lowland and highland maize. The third objective is to characterize the functional consequences of an adaptive inversion polymorphism via phenotypic and transcriptomic evaluation of introgression lines. This basic research will be complemented by outreach activities including phenotyping workshops to demonstrate high-throughput field data collection methods, student exchanges, and farmer field exhibitions in conjunction with a breeding center in Mexico.