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

西瓜是世界上重要的蔬菜作物，但由于对西瓜遗传学和地理范围的了解不足，目标育种受到阻碍。林奈根据意大利南部和西西里的栽培植物命名了这种作物西瓜，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和命名的南非物种混淆。这种混乱，加上地理上的采样不足，导致对西瓜的驯化以及西瓜的其他三个栽培品种，即Egusi甜瓜，保存甜瓜和colocynth的了解不足。该项目的目标是使用从纳米比亚，西瓜物种多样性中心，埃及和苏丹，具有最古老的考古植物学记录的国家的标本馆标本和新鲜收集的材料的基因组略读，以解决该属的物种边界和分歧时间，只有七个物种，其中两对涉及作物及其野生亲属。目前，西瓜的驯化研究还处于起步阶段。已经从考古遗址中种子的线性测量中推断出来。我们将使用3D几何形态测量学，使用计算机断层扫描（CT）的化石和最近的种子的所有物种，以测试种子识别的可靠性，并获得有关过去的物种范围和西瓜驯化的额外信息。该项目结合了实地收集，形态分析，地理学和系统发育的方法。

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.