IN VITRO GERMINATION AND CULTURE OF SOUTH AFRICAN ORNAMENTAL BULBOUS SPECIES SUITABLE FOR CULTIVATION IN MEDITERRANEAN-TYPE CLIMATE AREA OF THE NORTHERN HEMISPHERE

Abstract

Five geographical areas in the world are characterized by a Mediterranean-type climate. The same climatic characteristics allow species exchange and reciprocal acclimatization. From the South African Cape Region 5 bulbous species (Aristea capitata (L.) Ker Gawl., Bulbinella nutans (Thumb.) T. Duran & Schinz, Massonia depressa Houtt., Romulea hirsuta (Steud. Ex Klatt) Baker and Babiana rubrocyanea (Jacq.) Ker Gawl) have been selected for ornamental features to evaluate the cultivation suitability in the Mediterranean basin. The seeds were characterized for morphological parameters to set up a suitable protocol for desinfection and germination in vitro. Germination was carried out in light and in dark conditions and was extremely scarce for B. nutans (rooting only in light) but very good for M. depressa (100% germination both in light and in dark). Aseptic seedlings and buds sprouted from corms of B. rubrocyanea were multiplied in vitro on MS based media containing indole-3-butyric acid (IBA, 0.75 mg L-1) with multiplication rates ranging from 1.3 to 2.9 shoots per explant per month. The quality of the material during the vitro cultivation was good without callus formation and with the contemporary presence of roots. This is an essential prerequisite for a fruitful transfer in the acclimatization greenhouse. After these trials it is possible to indicate that in vitro culture of the selected South African bulbous species could be a valid alternative technique to improve a wide spread on the ornamental market.