Genetic diversity analysis and fingerprint map construction of sweetpotato based on agronomic traits and molecular markers

【Objective】The purpose of the study was to analyze the genetic diversity and construct a fingerprint map of sweetpotato varieties in Fujian based on agronomic traits and molecular markers, so as to provide a theoretical basis for the study of parent selection and genetic background of sweetpotato breeding in Fujian. 【Method】Twenty-four sweetpotato varieties bred and introduced in Fujian were used as research subjects to investigate and determine their agronomic traits. The 28 ISSR primers and 27 SRAP primers screened were used for genetic diversity analysis. SPSS 26.0 was used to perform clustering analysis of agronomic traits using the intergroup connection method and the mean Euclidean distance method. NTSYS-pc 2.1 was used for molecular marker clustering analysis. The fingerprint map was constructed according to the ISSR and SRAP amplification results. 【Result】The results of agronomic traits clustering analysis showed that 24sweetpotato varieties were classified into three major groups at a Euclidean distance of 8. GroupⅠconsisted of Quanshu 76, Quanshu No. 12 and Longshu No. 14. GroupⅡcontained Xuzishu No. 2, Quanshu No. 10, Pushu 20, Fushu No. 24, Puzishu 18 and Funingzi No. 3. The remaining 15 species were classified in Group III. The 28 ISSR primers and 27 pairs of SRAP primers amplified 362 and 364 bands respectively, with a polymorphism ratio of 78.73% and 83.79%, and the polymorphism rate of some primers was as high as 100.00%. The average numbers of alleles(Na) were 1.7676 and 1.8307, respectively, the average numbers of effective alleles(Ne) were 1.4071 and 1.4631, the average Nei's gene diversity index(H') were 0.2435 and 0.2730, the average Shannon's information index(I) were 0.3705 and 0.4124, respectively. Based on ISSR molecular markers, the genetic similarity coefficients of the 24 sweetpotato varieties ranged from 0.674 to 0.851, and they could be categorized into three major groups at the genetic similarity coefficient of 0.728.GroupⅠcontained only Funingzi No. 3, groupⅡcontained Fushu No. 24,Xuzishu No. 2,Pushu 20,Pushu 53,Puzishu 18,Puzishu No. 3,Fushu 404 and Pushu 16, and the remaining 15 varieties were categorized into group III. Based on SRAP molecular markers, the genetic similarity coefficient of the 24 sweetpotato varieties ranged from 0.591 to 0.879, and they could be categorized into three major groups at the genetic similarity coefficient of 0.696. Group Ⅰ contained only Quanshu 76, group Ⅱ contained Puzishu 18 and Xuzishu No. 2, and the remaining 21 varieties were categorized into group Ⅲ. The primer UBC899 could be used to construct the fingerprint map of 24 sweetpotato germplasm resources.【Conclusion】ISSR and SRAP molecular markers are efficient in polymorphism detection, and both of them are suitable for genetic variation analysis of sweetpotato germplasm resources. The genetic diversity of the 24 sweetpotato materials for tes-ting is relatively rich, and the clustering results based on agronomic traits cluster results and molecular markers are similar but greatly different. The ISSR molecular clustering results are more consistent with the pedigree map of the germplasm resources, and the primer UBC899 can be used to distinguish the tested sweetpotato varieties.