Propagation of endemic and endangered Sternbergia lutea with a high ornamental value by bulb chipping and plant growth regulators

Autumn daffodil (Sternbergia lutea) is a rare and endangered bulbous plant with yellow flowers grown naturally in Iran and unfortunately for different reasons this plant is at the risk of eradication. Natural multiplication rate of S. lutea is low, thus propagation by chipping method is one inexpensive and simple way to overcome this problem. This research was therefore performed to investigate the propagation method in two experiments. In the first experiment, the effects of some plant growth regulators (PGRs) on induction and regeneration of bulblets from bulb chips (propagules) were evaluated. The propagules were prepared by chipping method and treated with indole butyric acid (IBA), gibberellic acid (GA3), benzyl adenine (BA), kinetin (Kin) and cycocel (CCC) at 100 and 200 mg L–1 concentrations for 2 h and then incubated for two months at 20 ±1°C. At the end of incubation, the results showed the highest percentage of concurrent bulblet + root regeneration (CBRR), number and fresh weight of bulblets related to 100 mg L–1 GA3. The highest percentage of only bulblet regeneration (OBR), only root regeneration (ORR) and non-regeneration were obtained at 200 mg L–1 IBA, 100 mg L–1 Kin and control (distillated water: DW) treatments, respectively. In the second experiment, the bulblets that had rooted from each treatment of the first experiment were planted and the produced bulbs were compared. The results indicated that the highest percentage of bulblet sprouting, bulb number and diameter were found at 100 mg L–1 GA3. Therefore, the application of GA3 with mentioned concentration is appropriate for vegetative propagation of this plant by bulb chipping.