甘薯（Ipomoea batatas (L.) Lam）是具有特殊保健功能的特色作物，迫切需要品种改良，近缘野生种是极其重要的基因来源。但栽培种甘薯为六倍体，基因组来源尚不清晰，已有研究表明，I. tabascana（4x）是栽培种甘薯最近的野生种之一，可能是甘薯进化中的关键物种。本研究前期已筛选出可识别甘薯染色体的重复序列标记Itf_1, Itf_2，并对I. tabascana进行了初步测序。在此基础上，拟通过重复序列FISH、cGISH、寡核苷酸库为探针的染色体涂色等现代细胞遗传学技术，建立I. tabascana染色体识别体系，观察其减数分裂染色体行为，构建其分子细胞遗传学图谱，分析其基因组结构特征，研究其与甘薯组另外13个物种的亲缘关系，探讨I. tabascana在甘薯组物种中的系统进化地位，了解甘薯多倍化进程，为甘薯野生种质资源的利用提供理论依据。

Sweet potato (Ipomoea batatas (L.) Lam) is a kind of special health functions crops, urgent need for improved varieties. The wild relatives are extremely important source of resistance genes. However, the cultivated sweet potato is hexaploid, and the genomic origin is not clear. Previous studies have shown that I. tabascana (4x) is one of the closest wild relative species of cultivated sweet potato and may be a key species in sweet potato evolution. The repeats named Itf_1 and Itf_2 from the I. trifida (2x) genome which can identify sweet potato’s chromosomes were screened in preliminary work of our lab. And we also sequenced the genome of I. tabascana with low coverage. On the basis of these studies, this project aims to establish I. tabascana chromosome recognition system, observe its chromosome behavior of meiosis, construct its molecular cytogenetic map and analyze its genomic structure by modern cytogenetic technologies. This research will help us to illustrate the genetic relationship between I. tabascana and other species in Batatas section, to better understand the phylogenetic status of I. tabascana in Batatas section and know the polyploidization process in sweet potato. Simultaneously, it provides a theoretical basis for sweet potato breeding by using wild relatives.