The conservation of potato cultivars

To prevent the loss-of important genetic information cultivars are conserve d in several collections of gene banks. In principal, there are two options for the medium to long-term storage of potato cultivars: storage as in vit ro plantlets or microtubers and storage of meristems or shoot-tips in liqui d nitrogen. In the Braunschweig potato cultivar collection, 360 cultivars a re maintained under slow-growth conditions. Ten microplantlets of each cult ivar are stored in test tubes containing filter paper bridges and 5 ml Mura shige and Skoog (MS) liquid medium. The cultures were maintained at 10 degr eesC with a light intensity of 2 klux and 16 hours-day and can be stored un der these conditions up to three years. Two hundred and forty-five cultivar s are cryostored in liquid nitrogen. About 300 trimmed shoot-tips of each c ultivar are incubated in MS-Towill-medium and then transferred into the cry oprotective solution. After an incubation time of about 2 hours trimmed sho ot-tips fixed on an aluminium foil were put in cryo vials and stored in a c ontainer. The survival rate of the thawed, trimmed shoot-tips varies from 5 5%-100%. More important for a gene bank, however, is the plant regeneration . The average regeneration of all cultivars is about 40%.