Virus-free plants of iris ‘wedgwood’ obtained by meristem culture

Some commercial varieties of Dutch (bulbous) iris such as ‘Wedgwood’ and ‘Imperator’ are wholly infected with a virus called latent mosaic virus in Israel or iris mosaic virus in the Netherlands. The aim of the investigation was to obtain virus-free plants of these varieties by culture of meristem tips excised from bulbs kept in their vegetative stage by storage at 25.5°C. Several media were used; those based on the medium ofMorel (personal communication) gave the best results. About 100 meristems were placed on each medium and on the best media about 30% started to grow. By transferring slowly growing meristems to the medium ofMurashige & Skoog (1962), growth improved greatly, though root formation remained poor. Twenty meristems developed into plants, of which ten were tested serologically. Eight plants of the variety ‘Wedgwood’ proved to be virus-free.