IN VITRO RAPID PROPAGATION OF RHODODENDRON CULTIVARS FROM CALLUS AND BUD CULTURES

For the experiments initial explants of Rhododendron were made from vegetative and flower buds on several dates from June to October and from November to April. The best growth and differentiation of tissue was obtained when initiating the culture in February and March, on a modified Anderson's medium with IAA 4 mg/l and 2iP 15 mg/l added. Flower pedicels cultured in the dark for an initial 3 weeks, then transferred to light for 6 weeks on a modified Economou and Read medium with low levels of growth regulators, produced more adventitious shoots then cultures from vegetative buds. The highest percentage of healthy and rooted cuttings was obtained in a non-sterile medium (peat + perlite 3:1) treated with Trichoderma viride and the fungicide - Benlate. Cuttings rooted in this medium formed the strongest root system and when grown as plants appeared normal in vegetative characteristics.