割手密资源是栽培甘蔗抗性基因的重要来源，加大其无性系的系统研究可提高其在甘蔗育种中的利用广度和深度。目前对割手密无性系间亲缘关系的研究多限于经典的细胞遗传学及分子标记水平，难以揭示这些资源植物间的亲缘关系、系统进化；同时，各基因型割手密的生态适应性也未明确，大大限制了其在甘蔗育种中的进一步利用。本项目拟对不同基因型割手密进行以下研究：（1）以5S及45SnrDNA、着丝粒DNA及端粒DNA重复序列荧光原位杂交(FISH)，分析割手密资源的染色体进化趋势；（2）对参试材料的各20个cpDNA和mtDNA基因保守序列进行扩增、测序及分析，构建这些材料的系统发育树并估测其起源和分化时间；（3）分析各材料的抗旱性、抗寒性等生理生化特性。通过以上研究探讨不同基因型割手密无性系间的亲缘关系、系统发生、进化及逆境生态适应性，为其采集、保存及在甘蔗育种中的进一步利用提供科学依据。

The wild sugarcane species Sacchrarum spontaneum L. germplasm resource is the important gene resource for drought resistance, cold tolerance, disease and pest resistance of cultivated sugarcane. To accelerate the use of S. spontaneum in sugarcane breeding and broaden the genetic base of sugarcane cultivars by using S. spontaneum germplasm for crossing, it’s essential to further study the relationship between different genotypes and the phylogenesis and evolution of S. spontaneum. So far, the study on the genetic relationship of different S. spontaneum clones is mainly focus on classic cytogenetics and molecular marker methods, it’s difficult to revel the relationship, phylogenesis and evolution between these germplasm plants by these methods, and the further use of these germplasm plants in sugarcane breeding program is limited because their ecological adaptability is still unidentified. In this project, the 5S and 45SrDNA genes, repeat sequences of centromene and telomere will be used as probes to hybridize with the different genotypic S. spontaneum clones by fluorescence in situ hybridization (FISH) to analysis the chromosomal evolution of S. spontaneum resource; the most parsimonious tree will be built and the origin and diverging time will be estimated based on the suquences of the conservative DNA fragments and genes of chloroplast and mitochondrion; at the same time, the drought resistance and cold tolerance of these clones will be analysed by physiological and biochemical mthods. The objective of this study is to provide sentific support for the collection, preservation and application of S. spontaneum germplasm in sugarcane breeding by further study the relationship between different genotypes and the phylogenesis, evolution and ecological adaptability to abiotic stress of different genotypes of S. spontaneum.