MICROPROPAGATION OF GARLIC THROUGH INVITRO BULBLET FORMATION

We developed a novel micropropagation method for garlic (Allium sativum L.) by the combination of initial shoot-tip culture, shoot multiplication and in vitro bulblet formation. Garlic shoot-tips were cultured on LS medium containing 1 muM indole-3-acetic acid (IAA) and 1 muM 6-benzyladenine (BA) to regenerate proliferative shoots. These shoot-tips produced multiple shoots when transferred to modified LS medium containing 5 muM 1-naphthaleneacetic acid (NAA) and 10 muM BA, and cultured at 20-degrees-C under 12-h light conditions. Higher ratios of KNO3/NH4Cl in the media promoted multiple shoot formation, together with suppressing vitrification of these shoots. The proliferated shoots of early maturing cultivars produced bulblets by culture on LS growth regulator-free medium at 25-degrees-C under 16-h light. On the other hand, the late maturing cultivar, Howaito-roppen, formed bulblets after a low temperature treatment of the proliferated shoots for 6 months followed by culture on LS medium containing 6 to 12% sucrose for two months. The dormancy of the bulblets of cv. Howaito-roppen was broken by successive treatments at a high (35-degrees-C), a middle (20-degrees-C), and then a low (5-degrees-C) temperature.