AN IMPROVED MEDIUM FOR IN VITRO PROPAGATION OF GLOBE ARTICHOKE (CYNARA SCOLYMUS L.) CV.

Abstract

In vitro propagation of globe artichoke is mainly utilised for a few Spring cultivars and allows the production of plantlets for the distribution to the farmers. On the contrary, for the micropropagation of autumn cultivars much work is still needed to overcome the problems of the loss of earliness in a significant part of micropropagated plants. We report the development of a new culture medium suitable for the micropropagation of different globe artichoke cultivars. The modification of nitrate composition of the basal medium (NH(4)NO(3), 400 mg l(-1), KNO3, 800 mg l(-1), and Ca (NO(3))2 x 4H(2x), 1000 mg l(-1)), has allowed the production of shoots of good quality with leaves 5-6 cm in length and characterised by an entire edge. The same results were obtained also starting from shoots showing leaves with serrate edge, a morphology frequently associated with juvenility and correlated with late flowering plants in the field. The rate of multiplication of the material was modulated by using different citokinin (Kinetin or BAP) contents and a low IBA concentration (0.1 mg l(-1)). The use of 2 mg l(-1) Kinetin has allowed maintaining a good rate of shoot proliferation together with a good quality of the shoots, while BAP at 0.8-2.0 mg l(-1) concentration gave rise to a high number of small sized shoots. About 90% of the shoots rooted after the transfer for a week on a medium containing 10 mg l(-1) IAA and then to a hormone free medium. Most of the rooted shoots survived when transferred to pots containing a mixture of soil and perlite.