Impact of Different Explants and Growth Regulators on In vitro Regeneration of Chrysanthemum

Chrysanthemum is the world’s second most economically important flower crop and commonly known as ‘Autumn Queen’. It belongs to the family Compositeae (Asteraceae). It is native to Asia and northeastern Europe and has been cultivated for more than 2000 years. The present study within vitro regeneration of chrysanthemum was carried out to develop the standardized protocol for organogenesis. In this study, three types of explants viz. apical shoot tip, internodal segment and young leaf along with different concentrations and combinations of growth regulators were used for in vitro regeneration. BAP and KIN were used for in vitro microshoot regeneration and IBA along with 2, 4-D were used for in vitro microroot regeneration. Minimum days (7.00) for microshoot initiation, maximum microshoot initiation percentage (97.00), highest number of microshoot per plantlet (12.00), highest number of leaves per microshoot (14.60) and maximum microshoot length (4.60) at 28 DAC were recorded as best performances by apical shoot tip inoculated into MS medium supplemented with BAP 2.5 mg/L + KIN 0.5 mg/L. On the other hand, minimum days (5.00) for microroot initiation, maximum microroot initiation percentage (97.60), the highest number of microroots per plantlet (11.80) and maximum microroot length (6.20) were obtained from apical shoot tip inoculated into ½ strength MS medium supplemented with IBA 0.2 mg/L + 2, 4-D 0.1 mg/L. In case of microshoot regeneration, the best response was showed by apical shoot tip when inoculated into MS medium supplemented with BAP 2.5 mg/L + KIN 0.5 mg/L and the microrooting of plantlets were best from apical shoot tip inoculated into ½ MS medium supplemented with IBA 0.2 mg/L along with 2, 4-D 0.1 mg/L.