A comparison of four selective agents for use with Allium cepa L. immature embryos and immature embryo-derived cultures

The efficacy of antibiotics, kanamycin, hygromycin, and geneticin, and the herbicide phosphinothricin as selective agents in onion (Allium cepa L.) tissue culture was investigated. Immature embryos and immature-embryo-derived cultures were grown on media containing a range of concentrations of the four selective agents. Kanamycin was shown to be unsuitable while phosphinothricin, geneticin or hygromycin significantly reduced further growth of the onion cultures. The level of casein affected growth on medium containing phosphinothricin. The effectiveness of phosphinothricin was reduced when high levels (200 mg/l) of casein were present in the medium. Omission of casein reduced the shoot regeneration frequency from immature embryo cultures. Low levels of hygromycin (10–30 mg/l) reduced callus growth but significantly increased the regeneration frequency from immature-embryo-derived cultures. Received: 12 September 1997 / Revision received: 5 December 1997 / Accepted: 13 March 1989