广东割手密SSR遗传多样性分析

Gentic Diversity of Saccharum spontaneum L. from Guangdong Province Analyzed Based on SSR Markers

割手密是甘蔗近缘野生种之一，在甘蔗育种中具有重要地位和作用。本研究采用Genomic-SSR和EST—SSR两种类型分子标记对来自广东各个地区的67个割手密种质进行分析。在20对SSR引物上共检测到341个多态性条带，每个引物上的平均多态性为17．05，其中11个Genomic-SSR的平均多态性为20．82，9个EST-SSR的平均多态性为12．44。广东割手密在Genomic—SSR上的多态性显著高于EST-SSR上的多态性。Mantel Test分析表明：通过Genomic-SSR、EST—SSR以及Genomic-SSR＋EST-SSR三种方法所计算的试验材料的遗传距离矩阵之间都呈极显著相关（p〈0．01），说明应用两种类型SSR获得的各个材料间的遗传关系具有较高的一致性。广东割手密在20对SSR引物上的遗传多样性指数介于0．1064～0．2916之间，平均多样性指数为0．1943；各个材料间的遗传距离为0．0063-0．3082之间，平均为0．1935。UPGMA聚类分析表明：广东割手密之间的遗传关系和地理来源存在一定的相关，由南向北存在较为显著的地理分化。

Saccharum spontaneum L. is a wild relative of sugarcane, which has played a major role in the improvement of sugarcane varieties. In this study, 67 spontaneum accessions from the different territories of Guangdong province were genotyped with 20 pairs of simple sequence repeat （SSR） that were designated to Genomic-SSR and EST-SSR. Total 341 polymorphic bands were detected by the 20 pairs of SSR with an average of 17.05 polymorphic bands for each pair of SSR. The average polymorphic bands for Genomic-SSR and EST-SSR were 20.82 and 12.44, respectively, indicating that there were much more variations occurred at Genomic-SSR loci than that occurred at EST-SSR loci in Guandong spontaneum. Mantel Test showed that there was significant correlation （p〈 0.01） among the genetic distance matrixes of the tested materials calculated by Genomic-SSR, EST-SSR, and both of the two types of SSR. The results presented that there was high similarity in genetic relationship among the tested Guangdong spontaneum accessions applied to the two types of SSRs. Genetic diversity index of Guangdong spontaneum ranged from 0.106 4 to 0.291 6 with an average of 0.194 3, while genetic distance among Guangdong spontaneum ranged from 0.006 3 to 0.308 2 with an average of 0.193 5： Cluster analysis using the UPGMA method showed that there was a certain correlation between genetic relationship and geographical origin in Guangdong spontaneum, and significant geographic differentiation occurred from south to north.