The evolution and domestication of multiple crop species in the watermelon genus Citrullus

西瓜是世界范围内重要的蔬菜作物，但由于对西瓜的系统发育和地理范围了解不足，定向育种受到阻碍。林奈根据来自意大利南部和西西里的栽培植物给这种作物命名为西瓜，20世纪30年代的一次分类错误导致他的物种与他的一个学生收集并命名的南非物种混淆。这种混乱，再加上地理上的采样不足，导致人们对西瓜和其他三个栽培西瓜品种，即西瓜和西瓜的驯化缺乏了解。墨西哥甜瓜、蜜瓜和椰子。这个项目的目标是利用从纳米比亚、西瓜属物种多样性中心、埃及和苏丹等拥有最古老的考古植物学记录的国家收集的标本和新收集的材料的基因组，来解决这个仅有7个物种的属的物种边界和分化时间，其中两个物种对涉及一种作物和它的野生近亲。到目前为止，对西瓜的驯化主要是通过人工驯化来实现的。是从考古遗址种子的线性测量推断出来的。我们将使用计算机断层扫描(CT)对所有物种的化石和最近的种子进行3D几何形态测量，以测试种子识别的可靠性，并获得有关过去物种范围和西瓜驯化的更多信息。该项目结合了实地采集、形态分析、系统地理学和系统发生学方法。

Watermelons are important vegetable crops worldwide, but targeted breeding is hindered by insufficient understanding of Citrullus phylogenetics and geographic ranges. Linnaeus named the crop watermelon based on cultivated plants from southern Italy and Sicily, and a taxonomic misjudgment in the 1930s resulted in his species becoming confused with a South African species collected and named by one of his students. This confusion, combined with geographically insufficient sampling, has resulted in a poor understanding of the domestication of the watermelon as well as three other cultivated species of Citrullus, viz. the Egusi melon, the preserving melon, and the colocynth. The objective of this project is to use genome skimming of herbarium specimens and freshly collected material from Namibia, the center of Citrullus species diversity, Egypt, and Sudan, the countries with the oldest archeobotanical records, to resolve species boundaries and divergence times in this genus of just seven species of which two pairs involving a crop and its wild relative. Until now, the domestication of Citrullus spp. has been inferred from the linear measurements of seeds in archaeological sites. We will use 3D geometric morphometrics using computer tomography (CT) of the fossil and recent seeds of all species to test the reliability of seed identification and to obtain additional information about past species ranges and watermelon domestication. The project combines field-collecting, morphological analyses, phylogeographic, and phylogenetic approaches.