Micropropagation of garlic through in vitro 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 M indole-3-acetic acid (IAA) and 1 M 6-benzyladenine (BA) to regenerate proliferative shoots. These shoot-tips produced multiple shoots when transferred to modified LS medium containing 5 M 1-naphthaleneacetic acid (NAA) and 10 M BA, and cultured at 20°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°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°C), a middle (20°C), and then a low (5°C) temperature.Abbreviations IAA indole-3-acetic acid - NAA 1-naphthaleneacetic acid - BA 6-benzyladenine - LS Linsmaier and Skoog macro- and microelements