Indução e desenvolvimento de bulbos de alho in vitro por meio da vernalização de bulbilhos e da variação do fotoperíodo

In vitro morphogenesis of garlic plants (Allium sativum L.) is controlled by substances added to culture media and by environmental factors. The objective of this study was to assess the effects of vernalization of bulbils and of photoperiod on the process of in vitro induction of garlic bulbs. Shoot meristems were excised from bulbils vernalized for periods of 0, 30, 60 and 90 days and cultivated in vitro either under conditions of short photoperiod (11h) or long photoperiod (16h). Regardless of the photoperiod they were exposed to, plants micropropagated from meristems extracted from those bulbils vernalized for 30 or 60 days showed a rate of bulbing of 100%. Interaction between photoperiod and temperature was detected only in bulb fresh weight and plant height, thus showing the dependence between these environmental factors in the micropropagation of garlic. The time of exposure of plants to cold decreases the sensitivity to photoperiod for bulbing induction. Garlic plants grown in vitro present morphogenetic answers to the induction and development of thermo and photoperiod-dependent bulbils.