Applicability of two male specific DNA markers for sex identification of various Asparagus species

Garden asparagus (Asparagus officinalis) belongs to the genus Asparagus, which comprises more than 200 species. Some of the dioecious Asparagus species were found to be cross-compatible and interspecific hybridization was carried out to introgress agricultural traits of wild Asparagus species into garden asparagus. To date, several molecular marker techniques have been employed to identify sex-linked markers of garden asparagus and we developed two male specific markers, Asp1T7sp and MSSTS710. These markers were applicable to identify the sex of asparagus cultivars, such as ‘Mary Washington 500W’, ‘Super Welcome’, ‘Backlim’ and ‘Pacific 2000’. In this study, we analyzed the applicability of these markers to identify the sex of nine dioecious Asparagus species, A. officinalis, A. pseudoscaber, A. maritimus, A. kiusianus, A. schoberioides, A. verticillatus, A. stipuralis, A. acutifolius, and A. cochinchinensis. Asp1T7sp marker amplified male specific DNA fragment in A. officinalis, A. pseudoscaber, A. maritimus, A. kiusianus, and A. schoberioides, but not in A. verticillatus, A. stipuralis, A. acutifolius, and A. cochinchinensis. The applicable wild Asparagus species, A. pseudoscaber, A. maritimus, A. kiusianus, and A. schoberioides were cross-compatible with A. officinalis and phylogenetic analysis showed that these 5 species are all closely related members of a single clade. This indicates that DNA region around Asp1T7sp marker are well conserved in these 5 species. On the other hand, MSSTS710 marker amplified male specific DNA fragment only in A. officinalis. This indicates that MSSTS710 marker is applicable for sex identification only in A. officinalis and the genomic structure around MSSTS710 marker might be more variable among Asparagus species.