Species relationships among Allium species by ISSR analysis

Abstract

The genus Allium includes several important condiment and ornamental vegetable species. The botanical status of many more than 600 species in the genus Allium has not been clearly classified. We used inter simple sequence repeat (ISSR) technique to analyze the phylogenetic relationships among 24 individual accessions and species that represent cultivated Allium species and their ancestral species. Nucleotide sequence analysis was used to rule out homoplasy, the possibility that unrelated ISSR-bands migrated to the same positions during gel electrophoresis. To avoid spurious results, PCR reactions were conducted in duplicate on independent thermocyclers and only reproducible bands were used for analysis. We detected 153 polymorphic bands from 20 ISSR primers. The ISSR polymorphism profiles were used to group most of the Allium species and accessions according to previous classification. However, A. chinense, previously included in the Rhizirideum section, was distinct from other species in the phylogenetic dendrogram. A. wakegi, the Korean endemic ‘Jjokpa’ and hybrid between A. cepa and A. fistulosum, was grouped in the Cepa section. A. monanthum, another Korean endemic ‘Dalae,’ was grouped in the Rhizirideum section. Because phylogenetic analysis of these three Korean endemic species has not been reported previously, the current report may allow these species to be included in future phylogenetic studies.