The Origins of Domesticated Sunflower (Helianthus annuus L.)

在美国国家科学基金会的资助下，David Lentz博士和他的同事将进行实地考察和实验室实验，以确定现代驯化向日葵（Helianthus annuus L.）是否起源于：1)像之前假设的那样，来自北美东部种群的野生祖先；2)来自墨西哥的野生种群；或者3)两个独立的驯化事件的结果。由于最近在墨西哥塔巴斯科海湾沿岸地区圣安德烈斯遗址的深层沉积物中发现了完全驯化的H. annuus考古植物学遗迹，驯化向日葵起源的问题重新开始。放射性碳年龄测定+- 50 B.P.这些发现代表了驯化向日葵的最早的无可争议的记录。圣安德烈斯的葵花籽很可能是作为成熟的驯化品种进口到塔巴斯科的，因为塔巴斯科位于现代野生向日葵分布的南部。向日葵驯化的确切地点目前尚不清楚，但墨西哥韦拉克鲁斯北部有适宜的栖息地和野生种群的地区现在看来可能是向日葵的原产地。方法方法将包括一个主要的实地工作组成部分，然后是实验室分析。野外工作的重点是收集来自墨西哥北部、美国西南部和美国中西部的现代野生向日葵标本。这些标本将为分类和分子分析提供原料，使研究小组能够确定驯化向日葵的野生祖先种群。以前的作者根据密西西比河流域几个遗址的考古植物学数据，认为驯化向日葵起源于北美东部，并认为向日葵是最终发展成北美栽培的东部农业综合体（EAC）的关键物种之一。有趣的是，向日葵是唯一一种在北美东部驯化时没有受到挑战的主要作物；现在，这种起源，至少作为一种独特的驯化事件，似乎受到了质疑。除了人类学意义之外，确定野生种群祖先的位置对于扩大一种宝贵资源的遗传基础具有重要的实际应用；向日葵是世界上主要的油籽作物之一，全球年产量超过2600万吨。一旦定位，这些祖先向日葵种群作为宝贵的遗传库，将成为有意义的保护目标。

With funding provided by the National Science Foundation, Dr. David Lentz and his associates will conduct fieldwork and laboratory experiments to determine whether the modern domesticated sunflower (Helianthus annuus L.) is derived from: 1) a wild progenitor from populations in eastern North America, as previously hypothesized; 2) a wild population from Mexico; or 3) or the result of two separate domestication events. The issue of domesticated sunflower origins has been reopened because of recently discovered archaeobotanical remains of fully domesticated H. annuus from deep deposits at the San Andres site in the Gulf Coast region of Tabasco, Mexico. Radiocarbon age determinations +- 50 B.P. These findings represent the earliest indisputable record of domesticated sunflower. The San Andres sunflower seeds probably were imported into Tabasco as full-fledged domesticates because Tabasco lies to the south of the modern distribution of wild sunflowers. The precise location of sunflower domestication is unknown at present, but Mexican regions north of Veracruz with suitable habitat and wild populations of H. annuus now seem likely as possible areas of origin.The methodological approaches will include a major fieldwork component followed by laboratory analyses. The fieldwork will focus on collecting modern wild sunflower specimens from northern Mexico, the southwestern U.S., and the midwestern U.S. These collections will provide raw material for the taxonomic and molecular analyses that will enable the team to identify wild progenitor populations of domesticated sunflower.Previous authors have argued for an eastern North American origin for domesticated sunflower based on archaeobotanical data from several sites in the Mississippi River Basin and the recognition of sunflower as one of the keystone species in what eventually developed into the Eastern Agricultural Complex (EAC) of North American cultigens. Interestingly, sunflower was the only major cultigen that formerly was unchallenged as an eastern North American domesticate; now that origin, at least as a unique domestication event, appears in doubt. In addition to its anthropological implications, locating ancestral wild populations has significant practical applications for expanding the genetic base of a valuable resource; sunflower is one of the world's major oilseed crops with an annual global production of over 26 million metric tons. Once located, these ancestral sunflower populations, as valuable genetic reservoirs, will represent meaningful targets for conservation.