Effect of growth regulators on potted chrysanthemum under different photoperiodic conditions

Present study was conducted to determine the effect of growth regulators on potted chrysanthemum (Dendranthema grandiflora Tzvelev) under controlled and natural photoperiodic conditions in six inch plastic pots in naturally ventilated polyhouse. The experiment was laid out in a Completely Randomized Design (factorial) consisting of two cultivars i.e. ‘Ajay’ and ‘UHFSChr-Collection 1’ and seven treatments i.e. control (distilled water), paclobutrazol (60 and 90 ppm), daminozide (2500 and 3000 ppm) and ethephon (500 and 750 ppm) and replicated thrice. In general, controlled photoperiod, when applied was found better for flowering over natural photoperiod. Plant height was minimum under controlled photoperiod (39.86 cm) with improved quality of plants as compared to natural photoperiod (49.95 cm). Findings revealed that for the best quality pot mum production of chrysanthemum cultivar ‘Ajay’, the pot should be sprayed with 60 ppm paclobutrazol after one week of pinching. However, the pots of ‘UHFSChr-Collection 1’ under natural photoperiod should be sprayed with daminozide 3000 ppm and paclobutrazol 60 ppm under controlled photoperiod for highest quality pot mum production.