MICROPROPAGATION OF YERBA MATE (ILEX PARA GUARIENSIS ST HIL) - EFFECTOF EXPLANT ORIGIN ON ESTABLISHMENT OF IN-VITRO CULTURES

Nodal sections of Ilex paraguariensis St. Hil. tree were, cultured in vitro in order to establish micropropagation systems. The nutrient med ium contained the mineral salts and Vitamins of Murashige & Skoog (MS) medium at 1/4 strength, plus 3% sucrose. The explants were incubated at 27 degrees C, 14 h photoperiod (10W/m(2), supplied by fluorescent l amps Philips TLD 36W/84). Several experiments were done to determine t he appropriate source of explants. Shoots were readily obtained only w hen nodal sections dissected from greenhouse grown plants (which were obtained by rooting shoots from a 10 year-old tree) were cultured. The establishment of nodal sections dissected directly from field-grown p lants were never observed because of the high rate either of browning or of contamination with microorganisms.