Biotechnology uses diverse approaches for plant propagation, among them in vitro micropropagation and hydroponics, based on the plant's capacity for vegetative multiplication. Nowadays, the market demand of Helichrysum italicum is increasing for its valuable essential oils; however, seed quality and crops’ growth are variable. The aim of this study was to test different approaches for rapid multiplication of cultivars. Seeds and stem tips were used as initial material for in vitro cultivation (MS medium), and cuttings - for hydroponic propagation (Cutting board system, GHE) in culture rooms under 16/8 h photoperiod and 23±2°C temperature. In vitro cultures initiation was hampered by high microbial contamination: 55.8% of the seeds survived, and almost all leaf explants dropped out due to fungi or necrosis. Seed germination was stimulated with 0.1% GA₃ and increased up to 24.4%, while a fungi-free stem-tips culture was obtained on medium containing antibiotic. Subcultivation was tested on media supplemented with different plant growth regulators, and 6.4 new shoots per explant were obtained on the best medium containing 2 mg/l BAP and 0.2 mg/l NAA, for 8 weeks. Plants cultivated on MS control medium rooted spontaneously and some of them were ex vitro adapted to phytotron and then to а greenhouse. On the hydroponic system, 77.8% of the cuttings rooted; 76.2% of which were transferred to soil mixture, and 81.3% of the potted plants successfully adapted to greenhouse conditions. Vegetative rapid propagation of valuable H. italicum cultivars was proved to be feasible by both in vitro and hydroponic multiplication for a 6-month period.

Immortelle, in vitro micropropagation, soilless cultivation, essential oils

Asya Kozhuharova

V^th International Congress on Biodiversity: „Taxonomy, Speciation and Euro-Mediterranean Biodiversity“