Effects of benzyl adenine and gibberellic acid pre-treatments on dormancy release, flowering time and multiplication of oriental lily (Lilium longiflorum) bulbs

Abstract: Dormancy in Oriental lily bulbs (Lilium spp) is a major bottleneck in lily flower production by small scale farmers because they cannot afford expensive chilled bulbs that have been induced to break dormancy. Thus for developing alternative and low cost dormancy mitigation techniques, the study investigated the effects of lily bulb pre-treatments with benzyl adenine (BA) and gibberellic acid (GA3) on dormancy breaking, emergence rates, time to flowering and bulb multiplication. Bulbs were pre-soaked for 24 hours in prepared solutions of various concentrations of BA and GA3 (0; 25; 50; 100 and 150 mg/L) and their combinations, plus a positive control of chilled bulbs. An unbalanced factorial arrangement in a randomized complete block design with three replications was used. The experiment was repeated in two seasons. Results showed that treating bulbs with BA and GA3 significantly influenced dormancy breaking in both the trials and was comparable with the chilling treatment. The highest sprouting was observed in bulbs treated with 50 mg/L BA (92%) and 50 mg/L GA3 (96.67%) in both trials; compared to chilled bulbs with 100% sprouting. The number of days to 50% bulb emergence was significantly reduced in trial 1 with various combinations of GA3 and BA (50 mg/L:100 mg/L; 150 mg/L:100 mg/L and 150 mg/L :150 mg/L ). Combining the plant growth regulators also decreased the number of days to flowering; with 25 mg/L BA + 150 mg/L GA3; 50 mg/L BA + 100 mg/L GA3; 50 mg/L BA + 150 mg/L GA3 and 100 mg/L BA + 100 mg/L GA, respectively, significantly decreasing the number of days to flowering to 124 compared with 132 for the control in trial 2.