High frequency of shoot multiplication and bulblet formation of garlic in liquid cultures

In vitro shoot proliferation and bulblet production of garlic (Allium sativum L.) was studied in liquid cultures. Shoots grown in vitro were used as explants and were cultured in MS medium supplemented with 2% (w/v) sucrose and 0.5 mg l(-1) 2-iP. Three culture methods (semi-solid, liquid-immersion and raft) were compared for shoot proliferation. Explants in liquid (immersion) culture exhibited an increased multiplication rate and fresh weight of shoots after 3 weeks of culture as compared with the other treatments. Bulblet formation and growth were studied in liquid medium with different concentrations of sucrose (2-13%). MS medium containing 11% (w/v) sucrose was optimal for bulblet development and bulblets developed in this medium within 9 weeks in culture. The highest multiplication rate was (135 bulblets/explant) found when explants were cultured in bulbing medium (MS medium containing 0.1 mg l(-1) NAA+11% (w/v) sucrose) supplemented with 10 muM JA. Growth retardants CCC, B-9, ABA also promoted induction and growth of bulblets. Darkness promoted the bulblet induction and growth compared to light conditions (16-h photoperiod of 50 mumol m(-2) s(-1)). The dormancy of bulblets was broken by cold treatment at 4 degreesC for 8 weeks.