Micropropagation of wild species of the genus Asparagus L. and their interspecific hybrids with cultivated A. officinalis L., and verification of genetic stability using EST-SSRs

An efficient micropropagation method for asparagus species was developed in this study. The method allows the fast cloning of the elite genotypes from different asparagus species and the interspecific hybrids obtained from these species. Rhizome bud explants were disinfected using 3 g l(-1) of benomyl and 20 g l(-1) of sodium hypochlorite. Then, they were cultured on Asparagus Rhizome Bud Medium 3 (ARBM-3) consisting in modified Mu-rashige and Skoog medium with salts with EDDHA-Fe (85.7 mg l(-1)) instead of EDTA-Fe and vitamins, supplemented with 0.3 mg l(-1) NAA, 0.1 mg l(-1) KIN, 2 mg l(-1) ancymidol and 6 % sucrose. Results showed that the method developed produced high disinfection rates (70-95 %). More than 70 % of the explants developed shoots and the rooting rate on ARBM-3 medium was 30-45 %. The rooting rate increased to 60-85 % when the unrooted shoots were subjected to an additional cycle of rooting, reaching 100 % after two cycles of rooting. The multiplication was achieved through mechanical division of rooted shoot clusters growing in ARBM-3. The acclimatization rate of the micropropagated plantlets was higher than 90 %. The micropopagated plantlets were screened for somaclonal variation using 12 expressed sequence tag derived simple sequence repeat markers. The results confirmed the character "true to type'' of the plantlets, indicating that the method developed in this study can be used to successfully micropropagate asparagus species.